Stereotactic radiosurgery for metastatic spine tumors.

Spinal metastases invariably affect the majority of patients with cancer. Many will develop symptoms related to pain and disability from epidural spinal cord compression as well as pathologic fracture of the vertebrae. With the emergence of targeted systemic therapies and a better understanding of cancer biology, patients are living longer with bony metastases. This poses particular challenges, as palliation of pain and maintenance of local tumor control are paramount to quality of life and overall functional independence for these patients. Stereotactic radiosurgery (SRS) has emerged as a potent primary standalone and adjuvant treatment option for spinal metastases. To date, the primary indications for SRS include 1) upfront standalone treatment for painful bony metastases in the oligometastatic patient, 2) standalone or post-operative treatment following progression or recurrence of local disease despite previous conventional external beam radiation therapy (cEBRT), and 3) following surgery during which epidural disease is decompressed and the spine stabilized when indicated. SRS has demonstrated a significant advantage over cEBRT for tumors traditionally regarded as relatively radioresistant such as sarcoma, melanoma, renal cell carcinoma, non-small cell lung cancer and colon carcinoma.9 The radiobiological advantage of increased tumoricidal dose delivery and spinal cord dose sparing in SRS have made this a powerful treatment alternative to cEBRT particularly within the context of re-irradiation. Given the limitations of spinal cord dose constraints, surgery is still the first-line therapy in patients with high-grade epidural spinal cord compression (ESCC). Epidural compression can be treated with SRS, however this risks radiation-induced myelopathy and challenges the safety of effective dose delivery at the dural margin.11 With increasing dose, radiation-induced vertebral fracture is the most serious and prevalent side effect of SRS.53 An overview of SRS, including the most common indications, complications, and outcomes for spinal metastases are presented here.

Women in Neurosurgery: Historical Path to Self-Segregation and Proposal for an Integrated Future.

Despite the rising percentage of women accessing the medical profession over the last few decades, surgical specialties are still largely male-dominated; in particular, a remarkable gender disparity is evident in neurosurgery, where only 19% of practitioners are females. Although women may be reluctant to choose a challenging specialty like neurosurgery due to concerns around how to balance family and career, it must be admitted that prejudices against female neurosurgeons have been deeply rooted for long, prompting many to give up and switch track to less demanding subspecialties. Among those who have persisted, many, if not most, have experienced difficulties in career progression and received unequal treatment in comparison with their male counterparts. In 1989, a group of 8 female neurosurgeons founded Women in Neurosurgery (WINS), an organization that aimed to guarantee inclusivity in neurosurgery, encouraging a better and more egalitarian working environment. Thereafter, WINS sessions were regularly promoted at international conferences, offering female neurosurgeons a platform to report issues related to gender discrimination. Over recent years, the mission of WINS sessions in national and international conferences has taken an unexpected deviation; they have progressively become supplementary scientific sessions with only women neurosurgeons as speakers, thus paving the road to a form of self-segregation. This tendency has also resulted in the establishment of sections of only female neurosurgeons within some national societies. Although there remains a faction that fiercely supports the WINS mindset of reserved spaces for women, such segregation is an upsetting prospect for those who believe that science and professionalism have no gender; a growing part of the global neurosurgical community believes that the conception of a "female neurosurgery" and a "male neurosurgery" is misguided and counterproductive and consider the existence of the WINS as anachronistic and no longer necessary.

Robotic assisted spinal surgery--from concept to clinical practice.

After several years of product development, animal trials and human cadaver testing, the SpineAssist--a miniature bone-mounted robotic system--has recently entered clinical use. To the best of the authors' knowledge, this is the only available image-based mechanical guidance system that enables pedicle screw insertion with an overall accuracy in the range of 1 mm in both open and minimally invasive procedures. In this paper, we describe the development and clinical trial process that has brought the SpineAssist to its current state, with an emphasis on the various difficulties encountered along the way and the corresponding solutions. All aspects of product development are discussed, including mechanical design, CT-to-fluoroscopy image registration, and surgical techniques. Finally, we describe a series of preclinical trials with human cadavers, as well as clinical use, which verify the system's accuracy and efficacy.

Anterior cervical plating.

Although anterior cervical instrumentation was initially used in cervical trauma, because of obvious benefits, indications for its use have been expanded over time to degenerative cases as well as tumor and infection of the cervical spine. Along with a threefold increase in incidence of cervical fusion surgery, implant designs have evolved over the last three decades. Observation of graft subsidence and phenomenon of stress shielding led to the development of the new generation dynamic anterior cervical plating systems. Anterior cervical plating does not conclusively improve clinical outcome of the patients, but certainly enhances the efficacy of autograft and allograft fusion and lessens the rate of pseudoarthrosis and kyphosis after multilevel discectomy and fusions. A review of biomechanics, surgical technique, indications, complications and results of various anterior cervical plating systems is presented here to enable clinicians to select the appropriate construct design.

Evidence for cerebellar-frontal subsystem changes in children treated with intrathecal chemotherapy for leukemia: enhanced data analysis using an effect size model.

BACKGROUND: Following brain insult in early childhood, the later maturing neocerebellum and frontal lobes frequently show abnormalities. OBJECTIVE: To investigate the morphologic characteristics and function of a proposed cerebellar-frontal subsystem in children treated for acute lymphoblastic leukemia (ALL) with intrathecal methotrexate using quantitative magnetic resonance imaging, neuropsychological measures, nonlinear multiple regression analysis, and a statistical effect size model that augments interpretive validity of nonsignificant statistical findings, particularly from small sample size studies. DESIGN: Comparison and relationship of magnetic resonance imaging morphometry of cerebellar lobuli I-V and VI-VII and prefrontal cortices, and performance on 5 neuropsychological tests assessing visual-spatial attention, short-term memory, and visuomotor organization and coordination between childhood survivors of ALL and a matched control group. PARTICIPANTS: Ten childhood survivors of ALL treated between 1982 and 1989 with standard 3-year intrathecal chemotherapy, and matched control subjects. MAIN OUTCOME MEASURES: Morphometric results of cerebellar lobuli I-V and VI-VII and prefrontal cortices, and results of Trail-Making Tests, Rey-Osterreith Complex Figure Test, WISC-III Coding. RESULTS: Significant effect size model values for outcome measures in the ALL group support deficits in lobuli VI-VII and prefrontal cortices, and neuropsychological performance. Multiple regression analysis results were consistent with hypothesized involvement of a cerebellar-frontal brain subsystem. CONCLUSION: Treatment of children with ALL with intrathecal methotrexate before 5 years of age has structural and functional effects on the developing neocerebellar-frontal subsystem.

MRI morphometry of mamillary bodies, caudate nuclei, and prefrontal cortices after chemotherapy for childhood leukemia: multivariate models of early and late developing memory subsystems.

Neurotoxic intrathecal chemotherapy for childhood acute lymphoblastic leukemia (ALL) affects developing structures and functions of memory and learning subsystems selectively. Results show significant reductions in magnetic resonance imaging morphometry of mamillary bodies, components of the corticolimbic-diencephalic subsystem subserving functionally later developing, single-trial memory, nonsignificant changes in bilateral heads of the caudate nuclei, components of the corticostriatal subsystem subserving functionally earlier developing, multitrial learning, significant reductions in prefrontal cortical volume, visual and verbal single-trial memory deficits, and visuospatial, but not verbal, multitrial learning deficits. Multiple regression models provide evidence for partial dissociation and connectivity between the subsystems, and suggest that greater involvement of caudate may compensate for inefficient corticolimbic-diencephalic components.

Evaluation of CSF shunt function: value of functional examination with contrast material.

Functional positive-contrast shuntography includes a patency check of both limbs of the shunt and the shunt valve by fluoroscopy following the injection of an iodinated contrast agent (anatomic shuntogram) and an assessment of the adequacy of ventricular fluid drainage under physiologic conditions by using serial CT scans to assess the rate of iodine dissipation from the ventricular system (physiologic shuntogram). To demonstrate its efficacy and utility, 82 functional shuntograms were obtained in 55 patients. Fifty-one of the 82 studies were abnormal. Of these, 22 demonstrated patency of both the proximal and distal limbs with an accompanying slow dissipation of contrast material after injection (21 of 22 patients were adults). Eighteen of these 22 patients improved following the reduction of shunt drainage pressure. In the case of frank shunt obstruction, the site of obstruction was delineated clearly in all 29 cases. Correlation of clinical outcome with test results confirmed the utility of this technique, especially when applied to the shunted adult hydrocephalic patient whose response to the shunt had been inadequate. The technique described here allows the clinician to differentiate between physiologic and anatomic shunt failure and between shunt failure and normal shunt function. It also allows for precise localization of the shunt obstruction in anatomic shunt failure and for demonstration of physiologic shunt failure when shunt patency is demonstrated in the presence of the slow dissipation of intraventricular contrast medium.

Preoperative spinal angiography for lateral extracavitary approach to thoracic and lumbar spine.

PURPOSE: To establish the safety, efficacy, and value of preoperative angiography in the surgical management of thoracic and lumbar spine disease, in which it is important to avoid injury to the artery of Adamkiewicz or other vessels that supply the spinal cord. METHODS: Sixty-one patients were evaluated primarily using digital subtraction angiography, low-osmolar or nonionic contrast agents, selective catheterization limited to the region of disease, and careful angiographic techniques. RESULTS: Two minor (small hematomas of the groin) and no major complications of angiography were encountered. Arterial supply to the spinal cord was identified in 22 patients. In 17 patients (77%), the arterial supply was in the region of planned surgery. In each of these patients the surgical approach was altered, either by dictating the use of a posterior surgical approach (four patients) or by altering the side of the lateral extracavitary approach (13 patients). CONCLUSION: Spinal angiography is a safe preoperative examination for thoracic and lumbar spine surgery. It is specifically useful when the lateral extracavitary surgical approach to spinal cord decompression and fusion (which predictably interrupts the terminal end-arterial blood supply to the spinal cord, if present) is planned.

Metrizamide shuntography for evaluation of shunt malfunction in hydrocephalus.

Ventricular shunts were evaluated by a shuntographic technique using metrizamide for the contrast material and delayed spot films and computed tomography (CT) to evaluate shunt function. Thirty hydrocephalic patients were studied who had clinical presentations of shunt malfunction. Fifty-two shuntograms were obtained; most demonstrated the cause of shunt malfunction. No contrast-related complications resulted from the procedure. Diagnostic accuracy was greatly improved by this method, since both anatomic and functional evaluations could be performed. In patients with normal studies, unnecessary surgery was eliminated; in abnormal shuntograms, the duration of surgery and the likelihood of complications were reduced because the surgeons knew the exact anatomic derangements to be corrected.

Functional recovery after decompressive spine operation for cervical spine fractures.

Ninety-nine patients with cervical spine fractures from C-4 through C-7 were operated upon from 1975 to 1981. Operation was performed to restore normal relationships between the spinal cord and roots and the spinal canal and foramina and to maintain these relationships by fusion when necessary. Neurological function was recorded pre- and postoperatively using a functional scale. Satisfactory fusion without adverse change in vertebral alignment was achieved in each patient. The average interval between injury and operation was 29 days. When neurological recovery was observed, it began promptly after operation, suggesting a cause and effect relationship.

Functional recovery after decompressive operation for thoracic and lumbar spine fractures.

A series of 105 operative cases of thoracic and lumbar spine trauma is presented. All patients underwent an anterior decompression and fusion via the lateral extracavity approach with or without an accompanying posterior internal stabilization procedure (modified Weiss springs or Harrington distraction rods). All patients were allowed to plateau neurologically before reconstructive spine surgery was performed. The patient's neurological grade at the time of surgery and after recovery was assessed according to a seven-grade scale presented herein. None of the 34 patients with a motor and sensory complete myelopathy recovered any function below the level in injury. Of the 10 motor-complete patients with some sensory perception, 4 improved neurologically; however, only 1 of these improved to a state of limited ambulation. The rest remained nonambulatory. Of the 33 patients with significantly disabling incomplete motor and sensory myelopathies, 17 improved to a level of minimal neurological deficit; only 3 patients were left nonambulatory. Of the 21 patients whose physical finding demonstrated a minimal neurological deficit preoperatively, 17 recovered to a normal neurological state. Seven patients were neurologically normal preoperatively and were unchanged postoperatively. Reconstruction of the spine with an anterior decompression and an accompanying stabilization procedure, when appropriate, leads to a better neurological outcome than that expected with either a conservative, nonoperative approach or an operative posterior stabilization approach.

Recovery of nerve root function after complete quadriplegia from cervical spine fractures.

Thirty-five patients with complete myelopathies secondary to cervical spine fractures from C-4 to C-7 underwent spinal decompressions and fusions between 1975 and 1981. Twenty-five of these patients underwent simultaneous nerve root decompressions, 23 with an accompanying anterior decompression and fusion and 2 with an accompanying posterior fusion. Substantial recovery of nerve root function occurred in 15 of these patients. A posterior reduction and fusion without nerve root decompression was performed in each of the remaining 10 patients. None of these patients demonstrated a significant improvement neurologically. Operation for nerve root decompression is indicated in selected victims of spinal cord injury.

Operative stabilization of the posttraumatic thoracic and lumbar spine: a comparative analysis of the Harrington distraction rod and the modified Weiss spring.

To assess the efficacy of operative stabilization techniques, a retrospective study of Harrington distraction rod (HDR) and modified Weiss spring instrumentation was performed in 90 patients. An operation was performed for one or both of two indications: persistent spine instability or the presence of a neurological deficit in patients with incomplete neurological injuries and myelographic evidence of spinal cord or cauda equina compression. The lateral extracavitary operative approach to the spine for decompression and anterior interbody fusion was performed with an accompanying HDR (47 patients) or modified Weiss spring placement (43 patients). Eight HDRs failed, resulting in gross instability (17 per cent) that either resulted in further neurological injury (1 patient), further surgery (2 patients), or increased morbidity secondary to prolonged bed rest (5 patients). One Weiss spring failed, requiring further surgery (2.3 per cent). Nonsurgical complications were similar in both groups and appeared to be unrelated to the type of instrumentation utilized. The modified Weiss spring instrumentation technique, which offers a dynamic compression fixation of the spine, was clearly superior to the HDR technique, which offers a rigid distraction fixation. The biomechanics of distraction versus compression and rigid versus nonrigid spine stabilization are discussed.

Correlation between sex hormone binding and peritumoral edema in intracranial meningiomas.

Estrogen and progesterone receptor binding activity was measured in 22 intracranial meningioma surgical specimens. None of the tumors was estrogen receptor-positive, whereas 19 were progesterone receptor-positive. Of these 19 patients, all demonstrated significant computed tomographic (CT) evidence of peritumoral edema. None of the 3 patients who lacked progesterone receptor binding had CT evidence of peritumoral edema (P less than 0.005). Peritumoral edema associated with intracranial meningiomas seems to be related, at least in part, to progesterone binding activity. This implicates the potential use of progesterone antagonists for the treatment of incompletely resected or recurrent meningiomas.

Surgical needle design: torsion resistance.

OBJECTIVE: The interface between a surgical needle and forceps affects needle-forceps stability. Stability has become more important with the introduction of blunt-point surgical needles. The stability at the needle-forceps interface can be assessed by quantitating resistance to both rotation and twisting. Two commonly used surgical needles are the MO and CT needles, which are particularly useful for soft tissue closure for which significant strength of closure is required. Their comparison is thus of importance to surgeons. The design of the MO needle (greater flat section width than the CT needle) should allow for a greater resistance to rotation at the needle-forceps junction. This theoretically makes the MO needle a better choice when blunt-point needles (which require a greater force to penetrate tissue) are used. The objective of this study is to document and quantitate the differences, if any, between the CT and MO needles with regard to rotation and twisting at the needle-forceps junction. METHODS: To compare the efficacy of the CT and MO needles with regard to needle-forceps stability, the resistance of the needles to rotation and twisting was assessed using a Hios HP-10 digital torque meter. RESULTS: The resistance to twisting of the CT and MO needles was not significantly different. However, the MO needle is 25% more resistant to rotation than the CT needle. This differed by 10% from the expected difference. CONCLUSION: The resistance to twisting is not significantly affected by needle geometry, whereas the resistance to rotation is significantly affected. The difference between expected and observed differences in rotation is explained by study design.

Lateral extracavitary approach for thoracic and thoracolumbar spine trauma: operative complications.

BACKGROUND: The lateral extracavitary approach (LECA) to the thoracic and thoracolumbar spine allows ventral decompression and dorsal fixation of the spine through the same incision during a single procedure. The approach, however, is technically demanding and time-consuming. We sought to determine the incidence of complications associated with the LECA in patients with acute thoracolumbar spine injuries. PATIENTS AND METHODS: A retrospective chart review of all patients with acute fractures or dislocations of the thoracic or thoracolumbar spine who underwent surgery via the LECA was conducted to assess the incidence and type of perioperative complications associated with the LECA. RESULTS: Thirty-three patients with thoracic or thoracolumbar spine injuries treated using the LECA between June 1990 and June 1996 were identified and had available medical records. Complications occurred in 18 of these patients. Pulmonary complications predominated. Eleven patients required tube thoracostomy for hemothorax or persistent pleural effusions, and seven patients developed postoperative pneumonia. There were no cases of neurological worsening. There was no mortality. CONCLUSION: Decompression and stabilization of acute thoracolumbar fractures with the LECA in the acute setting is associated with a 55% incidence of morbidity. Whereas some of this morbidity may be attributed to the effects of the injury, there is a certain intrinsic morbidity associated with the LECA. Although this morbidity may compare favorably with that of sequential ventral/dorsal approaches, the biomechanical advantages obtained with a combined ventral and dorsal construct must be balanced against the inherent morbidity of such approaches.

Computed tomography of traumatic atlantooccipital dislocation.

Although atlantooccipital dislocation is a well-recognized radiological entity, its computed tomographic (CT) recognition has not been previously described. It is the purpose of this report to show the complementary role of CT in precisely defining the abnormalities in both the coronal and the sagittal reconstruction planes. A case is presented and the literature is reviewed.

Civilian gunshot wounds to the spinal cord and cauda equina.

We evaluated 42 patients with neurological deficits after civilian gunshot wounds to the spine. Thirty-five of these patients (the study population presented here) received their initial and follow-up care at Louisiana State University Medical Center in Shreveport over a 4-year period. Each patient had incurred a single gunshot wound to the spinal cord or cauda equina with an accompanying neurological deficit. The patient population was divided into three groups. Group 1 patients had incurred a complete motor and sensory loss below the injury (20 patients (57%]. Group 2 patients had incurred incomplete spinal cord injuries (9 patients (26%], whereas Group 3 patients had cauda equina injuries (6 patients (17%]. Myelography was performed for all Group 2 and 3 patients as well as Group 1 patients in whom the trajectory of the bullet did not explain a higher level of neurological injury (3 patients (15%]. A decompressive operation was performed in the patients whose myelography showed neural compression. Three patients in Group 1 (15%), 5 patients in Group 2 (56%), and 5 Group 3 patients (83%) underwent operation. All 3 Group 1 patients who underwent operation had some improvement of nerve root function postoperatively. All operated Group 2 and 3 patients had improvement of myelopathic or radicular function postoperatively. All began improving within several days of operation, implying a cause and effect relationship. None of the 17 nonoperated Group 1 patients improved neurologically, whereas 3 of the 4 nonoperated Group 2 patients improved. The single nonoperated Group 3 patient improved neurologically.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurological improvement associated with late decompression of the thoracolumbar spinal cord.

We reviewed the cases of 20 patients admitted to our institution with thoracolumbar spinal cord injury who had previously undergone laminectomy and/or spinal instrumentation. Thirteen patients had a mass in the spinal canal, and 7 had kyphotic deformities. The lateral extracavitary approach to the spine and posterior stabilization when indicated were done in each. Seventeen patients obtained substantial neurological improvement. All 7 patients with kyphosis regained the ability to walk, as did all but 3 of the nonambulatory patients with a mass in the spinal canal. Morbidity was limited to pneumothorax and 1 case of late kyphosis associated with premature removal of the spinal fixation devices. Elective anterior approaches for reconstruction of the spinal canal with appropriate stabilization afford the best opportunity for neurological improvement in cases of thoracolumbar spinal cord injury.

Effect of dosage and timing of administration of naloxone on outcome in the rat ventral compression model of spinal cord injury.

The effect of the dosage and timing of administration of naloxone after spinal cord injury in rats via the ventral compression technique is presented. The rat ventral compression technique allows for a ventral compression of the spinal cord without the requirement of a previous laminectomy. It therefore facilitates the creation of an experimental lesion that is similar to that observed in the human clinicopathological situation. The first part of the two-part study presented herein involved the determination of the optimal dose of naloxone, administered intraperitoneally 45 minutes after the creation of the lesion. Of the groups studied (control group through 10.0 mg/kg group), 2.0 mg/kg of naloxone proved to be superior to both lesser and greater dosages. The second part of the study involved the administration of a 2.0 mg/kg dose of naloxone at varying intervals ranging from 10 minutes before lesioning to 24 hours after lesioning. A multiphasic response was again demonstrated, with an optimal time of administration occurring 45 minutes after the creation of the lesion. A significant effect was offered by a midrange dose of naloxone (2.0 mg/kg), administered at 45 minutes after injury (P less than 0.02 by analysis of variance and Duncan's multiple range test). These findings are discussed with respect to recent evidence regarding the effects of narcotic antagonists on both mu and kappa narcotic receptors. Past and future experiments must account for these responses to multiphasic dosage and timing of administration. Failure to do so may lead to erroneous conclusions.