bluuebunny/crossref_metadata_2025 huggingface dataset:
The pathophysiology of thoracic disc disease
Authors: Mcinerney James , Ball Perry A.
Published: January 2008

Nucleus pulposus herniations are far less common in the thoracic spine than at the cervical and lumbar regions. Traditionally, diagnosis of thoracic disc herniations has been challenging because the signs and symptoms are often subtle early in their course. As a result, delays in diagnoses are common. Because they are uncommon as well as difficult to diagnosis, the neurosurgical community has sparse data on which to base good clinical decision making for the treatment of these herniations.

In this review the authors seek to place the phenomenon of thoracic disc disease into the context of its pathophysiology. After a careful evaluation of the available clinical, pathological, and basic science data, a case is made that the cause of nucleus pulposus herniations in the thoracic spine is similar to those occurring in the lumbar and cervical regions. The lower incidence of herniations is ascribed primarily to the reduced allowable flexion at the thoracic level compared with the lumbar and cervical levels. To a lesser extent, the contribution of the ribs to weight-bearing may also play a role.

Further review of clinical data suggests that thoracic disc herniations, like herniated cervical and lumbar discs, may be asymptomatic and may respond to conservative therapy. Similarly, good surgery-related results have been reported for herniated thoracic discs, despite the more challenging nature of the surgical procedure.

The authors conclude that treatment strategies for thoracic disc herniations may logically and appropriately follow those commonly used for the cervical and lumbar levels.
Imaging-guided costotransversectomy for thoracic disc herniation
Authors: Kim Kee D. , Babbitz Jesse D. , Mimbs Jeffrey
Published: January 2008

The surgical management of thoracic disc disease remains challenging. Outcomes after laminectomy had been poor, and modern posterolateral, lateral, and anterior approaches have evolved to replace this older procedure. Each has its own set of complications, and all are hampered, to varying degrees, by the limited visualization of the ventral disc space and spinal cord during decompression. The authors present their early experience with computer-assisted image guidance as an adjunctive tool for preoperative planning and navigation in the treatment of thoracic disc disease. Five consecutive patients underwent image-guided costotransversectomies between January 1999 and April 2000. The levels of herniation were T8–9 in three and T7–8 and T5–6, respectively, in the other two. There were four centrolateral herniations and one midline herniation. Three discs were soft and two hard. Two patients had previously undergone failed disc excisions. All patients had axial pain and myeloradiculopathies preoperatively. Three were unable to walk.

Four patients enjoyed good or excellent outcomes, with return of ambulation. One patient experienced only mild improvement in her severe paraparesis. Image-guidance was invaluable in planning the corpectomy and aiding visualization in situations in which the dura or disc were obscured; its use allowed successful surgical excisions in the most challenging circumstances.
Transthoracic approaches to thoracic disc herniations
Authors: Vollmer Dennis G. , Simmons Nathan E.
Published: January 2008

The transthoracic approach to herniated thoracic discs is an important procedure in the management of these uncommonly encountered lesions. Whereas posterior and posterolateral microsurgical approaches and thoracoscopic procedures have been widely advocated in the recent neurosurgical literature, the transthoracic operation continues to offer significant advantages in appropriately selected cases. The authors discuss the preoperative considerations, relevant anatomical structures, and surgical technique.
Global and regional techniques for monitoring cerebral oxidative metabolism after severe traumatic brain injury
Authors: Valadka Alex B. , Furuya Yu , Hlatky Roman , Robertson Claudia S.
Published: January 2008

The disturbance of normal mechanisms of oxygen delivery and metabolism is a hallmark of severe traumatic brain injury (TBI). In the past, investigations into the status of cerebral oxygen metabolism depended on changes in the differences in oxygen content between arterial and jugular venous blood. The development of jugular venous oximetry permitted continuous monitoring of jugular venous oxygen saturation, thereby overcoming earlier limitations caused by intermittent sampling. Neuromonitoring techniques that utilize only jugular vein sampling provide information only about global cerebral metabolism, but direct measurement of brain tissue oxygen tension via intraparenchymal probes makes possible the assessment of regional cerebral oxygen metabolism. Regional and global neuromonitoring techniques are not competitive or mutually exclusive. Rather, they are best regarded as complementary, with each providing valuable information that has a direct bearing on patient outcomes. The authors review the currently available techniques used in the monitoring of cerebral oxidative metabolism in patients who have sustained severe TBI.
Cytokine immunogene therapy
Authors: Glick Roberta P. , Lichtor Terry , Cohen Edward P.
Published: January 2008

The prognosis for patients with either a primary or metastatic brain tumor is poor. Clearly new forms of therapy to improve the long-term survival of patients with malignant brain tumors are urgently needed. The authors are in the process of developing a new and novel form of treatment for primary and metastatic brain tumors in which they use genes involved in growth repression. In particular most tumors fail to induce an antitumor immune response strong enough to kill the tumor. Under appropriate circumstances, however, immunity can be produced in unique structures on the tumor cells known as antigens. To prepare the vaccine, genes are transferred into a fibroblast cell line that causes the cell to produce cytokines, the potent proteins known to stimulate the immune system. These cells are subsequently injected into the tumor bed, resulting in the development of an antitumor immune response. In experiments described in this manuscript, the authors have investigated a number of ways of augmenting the immune response by administering this type of cellular vaccine. They found that mice with a primary intracerebral glioma, melanoma, or breast cancer treated with this allogeneic cytokine-secreting vaccine survived significantly longer than untreated mice. Additionally the vaccine was found to stimulate a systemic antitumor immune response, as shown by immunocyto-toxic studies, histopathological examination, and delayed immune memory responses. In summary, these results indicate that immunogene therapy is a promising new targeted therapy for the treatment of intracerebral malignant tumors.
Time course analysis and modulating effects of established brain tumor on active-specific immunotherapy
Authors: Liu Yang , Ng Ka-Yun , Lillehei Kevin O.
Published: January 2008

Object

There have been numerous attempts to establish an effective immunotherapy for the treatment of brain tumors. To date, reliable methods to manipulate the immune system for promoting brain tumor regression have been disappointing. Generation of active immune responses in most of these studies was only possible in the absence of viable tumor cells, suggesting that immunotherapy can only be used as preventive therapy. In few studies the investigators have demonstrated success in using immunotherapy to treat a preestablished intracranial tumor. Using the 9L intracranial glioma model, the authors sought to delineate the underlying mechanisms for these observations.

Methods

In animals vaccinated with irradiated 9L glioma cells and interferon-gamma 14 and 7 days prior to intracranial tumor cell challenge, a significant increase in survival was shown. In contrast, vaccinations applied 3 days prior to, at the time of (Day 0) or 7 days after intracranial tumor cell challenge failed to influence survival. Histological examination of brain tissue specimens obtained in animals vaccinated before or after tumor cell challenge showed no difference in the degree of peritumoral mononuclear cell infiltration. When activated spleen cells obtained obtained from these animals were assayed for cytotoxicity and proliferative capacity, only those spleen cells derived from animals vaccinated prior to intracranial tumor cell challenge showed enhanced activity.

Conclusions

These data support the presence of a strong modulatory effect of tumor on local and systemic antitu-moral immune response. This immunosuppression appears to be secondary to a direct effect on T-cell function. Reversal of this immunosuppression may be a useful adjunct to tumor vaccine therapy.
Treatment of a glioblastoma patient by vaccination with autologous dendritic cells pulsed with allogeneic major histocompatibility complex class I–matched tumor peptides
Authors: Liau Linda M. , Black Keith L. , Martin Neil A. , Sykes Steven N. , Bronstein Jeff M. , Jouben-Steele Lisa , Mischel Paul S. , Belldegrun Arie , Cloughesy Timothy F.
Published: January 2008

Dendritic cells (DCs) are antigen-presenting cells that play a central role in the initiation and modulation of antitumor immune responses. In this pilot study, we investigated the ability of autologous DCs pulsed ex vivo with allogeneic major histocompatibility complex class I–matched glioblastoma peptides to stimulate host antitumor immune responses when injected as a vaccine.

A patient with recurrent brainstem glioblastoma multiforme (GBM) received a series of three intradermal immunizations of antigen-pulsed DCs on an outpatient basis following surgical debulking of her posterior fossa tumor. Dendritic cell vaccination was well tolerated, and no clinical signs of autoimmunity or experimental allergic en-cephalomyelitis were detected. She developed a measurable cellular immune response against the allogeneic glioblastoma peptides used in her vaccine preparation, as demonstrated by in vitro T-cell proliferation assays. In addition, increased T-cell infiltration was noted within the intracranial tumor site in the biopsy sample obtained following DC vaccination. An objective clinical response, however, was not evident, and this patient eventually died 21 months after her disease was diagnosed.

To our knowledge, this is the first patient with brain cancer ever to be treated with DC-based immunotherapy. This case illustrates that vaccination with DCs pulsed with acid-eluted glioblastoma peptides is feasible and can induce systemic antigen-specific immunity in a patient with recurrent GBM. Additional studies are necessary to determine the optimum DC doses and antigen loading conditions that may translate into clinical effectiveness and survival benefit for patients with brain tumors. Phase I trials for malignant glioma are currently underway.
Spinal lipomas
Authors: Blount Jeffrey P. , Elton Scott
Published: January 2008

Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelome-ningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.
Long-term outcome for patients with split cord malformation
Authors: Proctor Mark R. , Scott R. Michael
Published: January 2008

Object

Split cord malformations (SCMs) are relatively rare forms of occult spinal dysraphism (OSD) and tethered spinal cord syndrome. The majority of these cases present in early childhood, with neurocutaneous stigmata being an early presenting feature. Prophylactic detethering surgery is advocated by most neurosurgeons due to the risk of neurological deterioration over time caused by patient growth and activity. However, unlike other forms of OSD, the course of SCM progression after surgery is not well understood, and little has been published about long-term follow-up results. In this study the authors review the results obtained in 16 patients in whom the senior author performed surgery over a 13-year period (average length of follow up almost 8 years).

Methods

Presentation, surgical approach, and outcome are evaluated, and the long-term outcome of neurological status, pain, bowel/bladder disturbance, and spinal deformities are emphasized.

Conclusions

The primary conclusion is that patients with SCM generally tolerate surgery well and experience few complications. Neurological deterioration is rare except in cases in which retethering occurs, (two patients in this series). Although impaired bowel and bladder function was stabilized or improved and pain was reliably relieved postoperatively, preexisting vertebral column deformities usually progressed after surgery and, in most cases, required spinal fusion.
Congenital tethered spinal cord syndrome in adults
Authors: Iskandar Bermans J. , Fulmer Benjamin B. , Hadley Mark N. , Oakes W. Jerry
Published: January 2008

Object

The management of tethered cord syndrome with onset of symptomatology occurring in adulthood remains controversial, although the necessity of early surgery in the pediatric tethered cord syndrome population is well established. To ascertain the results of surgery in adult patients with this anomaly, the authors undertook a retrospective review of 34 cases.

Methods

The authors studied the hospital records of 34 consecutive patients who presented in adulthood with tethered cord syndrome and conducted follow-up phone interviews with 28 of them. The population consisted of 12 men and 22 women, ranging in age from 18 to 70 years (mean 34 years). The most common presenting feature was pain, followed by weakness and incontinence. All patients underwent surgery. The most common operative findings were tight filum terminale, split cord malformation, and lipomyelomeningocele, paralleling those observed in pediatric studies.

Long-term surgical results and patient outcome ratings were encouraging. After a mean clinical follow-up period of 4 years, significant improvement occurred in 22 of 27 patients presenting with pain, 13 of 27 patients with motor or sensory dysfunction, and 11 of 18 patients with bowel and bladder disturbance. In addition, telephone interviews were obtained after a period of 8.6 years. Twenty-two (79%) of 28 patients called the operation a long-term success; 21 (75%) of 28 patients believed that they had significant postoperative improvement (and not just stabilization) in pain and/or neurological function. Surgical complications were generally minor.

Surgery-related complications included one cerebrospinal fluid leak and five pseudomeningoceles. Two patients complained of worsening motor or sensory dysfunction and one of worsening bladder dysfunction, whereas four patients experienced persistent pain and one complained of worsening pain postoperatively. According to the patients, the vast majority of these complications were minor.

Nineteen (86%) of 22 employed patients returned to work after surgery. Two (33%) of six patients who were not employed before surgery worked full time postoperatively. Only two of the 28 patients interviewed had received Workers' Compensation benefits; both of these had good outcomes and returned to work.

Conclusions

Tethered spinal cord syndrome in adults is an uncommon entity that can become symptomatic. Although surgery in adults involves greater risk of neurological injury than in children, it is a low-risk procedure with encouraging results. Because neurological deficits are generally irreversible, early surgery is recommended.
Refractory idiopathic intracranial hypertension treated with stereotactically planned ventriculoperitoneal shunt placement
Authors: Maher Cormac O. , Garrity James A. , Meyer Fredric B.
Published: January 2008

Object

Ventriculoperitoneal (VP) shunts have not been widely used for idiopathic intracranial hypertension (IIH) because of the difficulty of placing a shunt into normal or small-sized ventricles. The authors report their experience with stereotactic placement of VP shunts for IIH.

Methods

The authors reviewed the clinical records of all patients in whom stereotaxis was used to guide the placement of a VP shunt for IIH at their institution. All shunts were placed using stereotactic guidance to target the frontal horn of the lateral ventricle. Patients were contacted at a mean postoperative interval of 15.1 months. No patients were lost to follow up.

The authors identified 13 patients who underwent placement of a stereotactically guided VP shunt for IIH over a 6-year period. A trial of either acetazolamide or steroid therapy had failed in all patients. Prior surgical treatments included optic nerve sheath fenestrations in seven patients and cerebrospinal fluid diversionary procedures, other than stereotactic VP shunt procedures, in nine patients. Twelve patients reported excellent or good durable symptomatic relief at the time of follow up. No patient suffered progression of visual deficits. Four patients experienced persistent headaches following the procedure. Three patients required a revision of the VP shunt for technical failure.

Conclusions

Stereotactically guided VP shunt placement is an effective and durable treatment option in many cases of IIH that are refractory to more traditional medical and surgical approaches.
Image-guid ed thoracic pedicle screw placement: a technical study in cadavers and preliminary clinical experience
Authors: Kim Kee D. , Johnson J. Patrick , Babbitz Jesse D.
Published: January 2008

Object

Thoracic pedicle screw fixation is effective and reliable in providing short-segment stabilization. Although the procedure is becoming more widely used, accurate insertion of the screws is difficult due to the small dimensions of thoracic pedicles, and the associated risk is high due to the proximity of the spinal cord. In previous studies authors have shown the accuracy of image-guided lumbar pedicle screw placement, but there have been no reported investigations into the accuracy of image-guided thoracic pedicle screw placement. The authors report their experience with such an investigation.

Methods

To evaluate the accuracy of image-guided thoracic pedicle screw placement in vitro and in vivo, thoracic pedicle screws were placed with an image-guidance system in five human cadavers and 10 patients. In cadavers, the accuracy of screw placement was assessed by postoperative computerized tomography and visual inspection and in patients by postoperative imaging studies. Of the 120 pedicle screws placed in five cadavers pedicle violation occurred in 23 cases (19.2%); there was one pedicle violation (4.2%) in each of the last two cadavers. Of the 45 pedicle screws placed in 10 patients, pedicle violations occurred in three (6.7%).

Conclusions

In comparison with historical controls, the accuracy of thoracic pedicle screw placement is improved with the use of an image-guidance system. It allows the surgeon to visualize the thoracic pedicle and the surrounding structures that are normally out of the surgical field of view. The surgeon, however, must be aware of the limitations of an image-guidance system and have a sound basic knowledge of spinal anatomy to avoid causing serious complications.
Surgical approaches and strategies for skull base chordomas
Authors: Tamaki Norihiko , Nagashima Tatsuya , Ehara Kazumasa , Motooka Yasuhiko , Barua Kanak Kanti
Published: January 2008

Object

The management of chordomas involving the skull base continues to present a number of treatment-related problems. Recently, both radical resection and charged-particle irradiation or stereotactic radiosurgery have reportedly been found effective for tumor control and for promoting a better quality of life in patients. In this article the authors analyzed the outcomes in 17 patients with skull base chordomas who were surgically treated at Kobe University Hospital between 1972 and 2000.

Methods

Preoperative radiological examinations included magnetic resonance imaging, computerized tomography, angiography, and balloon occlusion test of the internal carotid artery. Among the various surgical approaches used to remove the tumor were the frontoorbitozygomatic, transmaxillary, transcondylar, transsphenoidal, and the transbasal. Total removal was achieved in two (12%), near-total removal in three (18%), subtotal removal in nine (52%), and partial removal in three patients (18%). Since 1990, chordomas have been radically resected via various skull base approaches; the combined total or near-total removal rate has been 80% in this period. Radical removal of the tumors has not led to an increased risk. At the final follow-up review (mean 59.5 month), 75% of the patients were still alive, and 25% had died of chordoma recurrence. The overall recurrence-free survival rate was 82% at 3 years and 51% at 5 years. The 5-year recurrence-free survival rate in the five patients who underwent the operation during the past decade was 77% (mean follow up of 5.2 years). In two patients with recurrent tumors who underwent radiosurgery, no evidence of tumor regrowth was demonstrated at 3 years posttreatment.

Conclusions

The authors suggest that for the treatment of skull base chordomas radical resection is a key factor for longer survival and improved quality of life. Patients with sufficiently small tumors, which show a favorable configuration and location, can be suitable candidates for stereotactic radiosurgery.
Review of skull base chordomas: prognostic factors and long-term results of proton-beam radiotherapy
Authors: Hug Eugen B.
Published: January 2008

Fractionated proton beam radiotherapy has been used for skull base tumors in the United States since the mid-70s, and more than 300 patients in whom diagnosis of chordoma of the skull base has been made have been treated. The ability to achieve high degrees of radiation dose conformity by using protons has resulted in higher radiation doses than can be delivered with conventional radiotherapy in the base of skull. High target volume doses have led to improved tumor control and patient survival. Side effects such as severe toxicity are acceptable considering the alternatives of uncontrolled tumor growth. The authors of various analyses have identified prognostic factors that can be used to predict a patient's chance of treatment success. On the horizon are important technical developments that will further increase dose conformity and increase target doses. In this paper the author reviews long-term outcome data and prognostic predictors for survival of patients with skull base chordomas based on the largest worldwide patient series.
Chordomas and chondrosarcomas of the skull base: results and complications of surgical management
Authors: Sekhar Laligam N. , Pranatartiharan Ramachandran , Chanda Amitabha , Wright Donald C.
Published: January 2008

Object

Chordomas and chondrosarcomas are rare and difficult to treat tumors for which the optimum treatment modality remains controversial. The aim of this study was to evaluate the surgery-related results and complications in a series of patients in whom radical resection was the treatment of choice.

Methods

The authors conducted a retrospective analysis of the surgery-related results and complications associated with chordoma and chondrosarcoma in 64 patients of whom 33 (52%) had previously undergone some form of treatment. Total or near-total excision was achieved in 56% and this rate increased to 68% in patients without prior treatment. The main complications were postoperative cerebrospinal fluid leakage, intraoperative arterial injury, and new-onset cranial nerve deficits. Arterial injury occurred only and perioperative death occurred more often in patients who had undergone previous treatment.

Conclusions

Analysis of the results provides support for a policy of radical excision of chordomas and chondrosarcomas at the time of first presentation. A higher incidence of procedure-related complications is found in patients who have already undergone surgery and radiotherapy.
Cranial chordomas: results of radical excision
Authors: Sen Chandranath , Triana Aymara
Published: January 2008

Object

The authors analyze their experience with the treatment of 29 patients who underwent radical excision of skull base chordomas.

Methods

Modern skull base surgical techniques were used in all patients who were treated between August 1991 and July 2000. The degree of tumor resection was gauged according to intraoperative inspection and postoperative high-resolution imaging findings. There were 21 patients with primary disease and eight with recurrent disease. Total resection was accomplished in 18 patients. Five patients had undergone radiotherapy prior to the present surgery, and an additional eight patients underwent postoperative radiotherapy. There were no surgery-related deaths. In five patients who died of the disease, surgery and radiotherapy had failed to effect a cure. Two of the remaining patients are alive with recurrent disease, and there is questionable evidence of recurrence in another patient. All 24 patients are functioning independently. Cranial nerve impairment was the most common postoperative deficit, followed by cerebrospinal fluid (CSF) leakage and infection.

Conclusions

The use of skull base techiniques in radical surgery provides an opportunity to excise the tumor and the involved bone. In most cases the procedure-related cranial nerve deficits improve over time. The complications of CSF leakage and infection can be minimized and are preventable. Proton beam irradiation is an excellent adjuvant treatment but is reserved for patients with definite tumor recurrence or residual tumor that can be identified on the imaging studies.
Suboccipital and cervical chordomas: radical resection with vertebral artery control
Authors: Carpentier Alexandre , Blanquet Alexandre , George Bernard
Published: January 2008

Object

Radical resection of chordomas seems to improve a patient's long-term prognosis. At the suboccipital and cervical levels, the vertebral artery (VA) is often considered as a limit in surgical possibilities. The authors report on the management of the VA in a series of 36 patients with chordomas located in the cervical region.

Methods

Over an 11-year period, 36 patients with chordomas located at the suboccipital (28 patients) or cervical (eight patients) level were treated in the authors' neurosurgical department. In 30 patients, the tumors extended laterally toward the VA and required surgical control of the VA. Sixteen of these 30 patients harbored primary tumor, whereas 14 were treated for recurrent disease.

The VA was encased in the tumor in 23 patients, with stenosis in six cases. A balloon occlusion test was performed in seven patients and the VA was resected in four. Extensive resection, via a lateral approach on one (22 cases) or on both (eight cases) sides, did not cause any permanent postoperative deficits. In five patients a complementary approach was performed: posterolateral in one and transoral in four. Spinal fixation was performed via the lateral approach (eight cases) or via a complementary posterior approach (five cases). All but two patients underwent radiotherapy, including 10 who underwent proton-beam radiotherapy.

Conclusions

Chordomas extending laterally to the VA can be radically resected via a lateral approach without causing significant morbidity. A complementary approach is often necessary. The best results are achieved in patients with primary compared with recurrent tumor.
Stereotactic radiosurgery and hypofractionated stereotactic radiotherapy for residual or recurrent cranial base and cervical chordomas
Authors: Chang Steven D. , Martin David P. , Lee Elizabeth , Adler John R.
Published: January 2008

Object

In patients with chordomas the lesions often recur. Furthermore, the location of some chordomas within the base of the skull and the cervical spine can prevent complete resection from being achieved. Previous series have shown that stereotactic radiosurgery can be used as a treatment for residual chordomas with good overall results. The authors review their experience in using linear accelerator (LINAC) stereotactic radiosurgery to treat patients with recurrent and/or residual cranial base and cervical chordomas.

Methods

Ten patients with chordomas (eight with cranial base and two with cervical lesions [below C-2]) underwent LINAC stereotactic radiosurgery. The mean patient age was 49 years (range 30–73 years). There were seven men and three women. Three patients had undergone one prior surgery, five had undergone two previous surgeries, and two had undergone three prior operations. The mean radiation dose was 19.4 Gy (range 18–24 Gy), and the maximum intratumoral dose averaged 27 Gy (range 24.1–33.1 Gy). The mean secondary collimator size was 14.4 mm (range 7.5–20 mm). The volume of the tumor treated ranged from 1.1 to 21.5 ml. In five patients a standard frame-based LINAC radiosurgery system was used, whereas in the other five the CyberKnife, a frameless image-guided LINAC radiosurgical system, was used. All patients were available for follow-up review, which averaged 4 years (range 1–9 years). Over the course of follow up, one chordoma (10%) was smaller in size, seven were stable, and two chordomas progressed (one in a patient who underwent reoperation and a second course of stereotactic radiosurgery, and the second in a patient who underwent reoperation alone). There were no new neurological deficits noted following radiosurgery in the eight of 10 patients in whom there was no tumor progression, and no patient developed radiation-induced necrosis.

Conclusions

Stereotactic radiosurgery can be used to treat patients with recurrent or residual chordomas with excellent tumor control rates. Longer follow-up review in larger series is warranted to confirm these findings.
Surgical seeding of chordomas
Authors: Arnautoviæ Kenan I. , Al-Mefty Ossama
Published: January 2008

Object

Chordomas have a high propensity for local recurrence and progression, as well as for systemic and cerebrospinal fluid metastasis. The authors identified and analyzed a series of patients with chordomas, focusing on an underrecognized entity—surgical seeding.

Methods

In a retrospective analysis of 82 patients with chordomas treated over a 10-year period (1990–2000) the authors found six patients (7.3%) in whom surgical seeding had occurred. In five (83%) of these patients the primary tumor was located at the clivus. In one (17%) the tumor was present in the cervical region. There were two male (33%) and four female patients (67%) with a mean age of 34 years. The seeding sites, which were separate from the primary tumor, were located along the operative route or in the abdomen where fat was removed. The seeding was diagnosed 5 to 15 months after surgery (mean 12 months). One seeding site was present in five patients and 17 seeding sites were present in one patient. The involved tissues included mucosa, bone, dura, muscle, and fat. After resection, all seedings were documented histologically.

Conclusions

Seeding of chordomas occurs along the operative route and at distant locations where fat is harvested. Early diagnosis and aggressive surgical treatment are recommended. Based on the results of this study, it is suggested that surgical techniques, postoperative irradiation, the neuroradiological follow-up protocol, and even research on chordomas should be reevaluated.
Pedicled rhinotomy for clival chordomas invaginating the brainstem
Authors: Harsh Griff , Ojemann Robert , Varvares Mark , Swearingen Brooke , Cheney Mack , Joseph Michael
Published: January 2008

Object

Clival chordomas are frequently midline lesions whose posterior growth may breach the dura and invaginate the brainstem. This precludes safe delivery of potentially curative high-dose fractionated proton radiotherapy. To avoid this problem, the authors performed pedicled rhinotomy to resect chordomas in 10 patients.

Methods

Pedicled rhinotomy is a midface transnasal route to the intercarotid sella and clivus from the tuberculum sellae to the mid-C-2 level. It involves a lateral rhinotomy incision, osteotomies of nasal bones and cartilage, lateral rotation of the nose, removal of the nasal septum and medial maxillary walls, opening of ethmoid and sphenoid sinuses, and dissection of nasopharynx and oropharynx to expose the clivus and craniovertebral junction. Tumors involving the sella, medial cavernous sinuses, middle and lower clivus, and C-1 arch and dens can be removed even if they traverse the dura. Closure involves dural repair, grafting of fat and split-thickness skin, rotation of a vascularized mucosal pedicle, and reattachment of nasal cartilage.

Ten clival chordomas in adult patients were surgically removed via a pedicled rhinotomy approach. Seven patients had previously undergone a total of nine skull base procedures. In eight of the 10 patients, tumors compressing the brainstem were completely removed using this technique. One patient required an additional subtemporal resection of a suprasellar tumor before definitive radiotherapy could be undertaken. No patient sustained any new neurological deficit; in eight patients headache, diplopia, or hemiparesis improved. One patient developed postoperative cerebrospinal fluid leakage and meningitis that were successfully treated with antibiotic agents and shunt placement.

Conclusions

Pedicled rhinotomy provides excellent shallow-field exposure of midline clival chordomas and permits relief of brainstem compression and the postoperative administration of potentially curative proton beam irradiation.
Posterior fusion compared with posterior interbody fusion in segmental spinal fixation for adult spondylolisthesis
Authors: La Rosa Giovanni , Cacciola Fabio , Conti Alfredo , Cardali Salvatore , La Torre Domenico , Gambadauro Nicola Maria , Tomasello Francesco
Published: January 2008

Object

Clinical and radiographic results in 30 consecutive patients who underwent posterior lumbar fixation and posterior facet joint or posterior interbody fusion for Meyerding Grade II/III spondylolisthesis were assessed: 1) to address the suitability of a dynamic stabilization; and 2) to investigate whether there are differences in terms of clinical and functional results and biomechanical properties between these two types of arthrodesis.

Methods

Between June 1998 and April 2000, 16 patients underwent posterior interfacet fusion and implantation of the SOCON-SRI system. In 14 patients posterior lumbar interbody fusion (PLIF) and placement of the same system were performed. Clinical, economic, functional, and radiographic data were recorded pre- and postoperatively.

The average changes in the Prolo Scale economic and functional scores were 1.25 and 1.62, respectively, in patients who underwent posterior fusion; the average measured preoperative vertebral slippage was 47.8% (range 30–65%), and postoperatively it was 18.5% (range 15–25%). In patients in whom PLIF was performed, the average changes in economic and functional score were 1.21 and 1.36, respectively, and the average preoperative vertebral slippage was 43.5% (range 30–55%) compared with 20% (range 15–25%) postoperatively.

Conclusions

The use of a segmental pedicle screw fixation with the SOCON-SRI system successfully combines the goal of solid fusion with the requirements of nerve root decompression. When the two fusion techniques were compared, an overall superior reliability and resistance of the systems was associated with the PLIF procedure (p = 0.04) but clinical outcomes did not differ greatly (p ≥ 0.05).
Percutaneous pedicle screw fixation of the lumbar spine
Authors: Foley Kevin T. , Gupta Sanjay K. , Justis Jeff R. , Sherman Michael C.
Published: January 2008

Object

Standard techniques for lumbar pedicle screw fixation involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine.

Methods

An existing multiaxial lumbar pedicle screw system was modified so that screws could be placed percutaneously by using an extension sleeve that would allow for remote manipulation of the polyaxial screw heads and remote engagement of the screw locking mechanism. A unique rod insertion device was developed that linked to the screw extension sleeves, allowing for a precut, precontoured rod to be placed through a small stab wound. Because the insertion device relies on geometrical constraint of the rod pathway through the screw heads, rods can be placed in a standard submuscular position with minimal manipulation, essentially no muscle dissection, and without the need for direct visual feedback. Twelve patients (six men and six women who ranged in age from 23–68 years) underwent pedicle screw fixation in which the rod insertion device was used. Spondylolisthesis was present in 10 patients and nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5–S1, three at L4–5, and one at L2–3), and two underwent two-level fusions (one from L–3 to L–5 and the other from L–4 to S–1). The follow-up period ranged from 3 to 12 months (mean 6.8 months).

Conclusions

Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience with this device has been promising.
Biomechanics of bone fusion
Authors: Kowalski Robert J. , Ferrara Lisa A. , Benzel Edward C.
Published: January 2008

Bone fusion can be achieved by one or more of three methods: in situ, onlay, and interbody fusion. Interbody implants provide the spine with the ability to bear an axial load. They function optimally when placed along the neutral axis and produce little, if any, significant bending moment. Interbody implants may be comprised of bone, non-bone materials such as acrylic, or a combination of both such as in interbody cages. In this report the authors' goal is to provide some insight into the theoretical, as well as practical, biomechanical factors that influence bone fusion, focusing on interbody implants. They review the concept of stress shielding and its impact on fusion. With the attendant biomechanical nuances of the different regions of the spine, they discuss region-specific strategies involved in successful fusion. Finally, they review intraoperative techniques that will improve the chance of achieving a successful arthrodesis.
Outcome analysis of anterior decompressive surgery and fusion for cervical ossification of the posterior longitudinal ligament: report of 107 cases and review of the literature
Authors: Mizuno Junichi , Nakagawa Hiroshi
Published: January 2008

Object

This study was designed to determine the surgical technique and surgery-related outcome, fusion rate, and complication of anterior decompression and fusion (with various graft materials) performed in patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

Methods

Between 1980 and 1998, 107 patients with radiologically proven OPLL underwent surgery via the anterior approach for direct removal of the ossified mass. Graft materials included iliac crest in 45 cases, vertebral body (VB) in 37 cases; and interbody fusion cages in 25 cases. In four patients with three-level VB grafts and one with a two-level VB graft, anterior plates were placed. Surgery-related outcome was excellent or good in 89% and fair in 11%. This clinical improvement correlated well with the severity of preoperative myelopathy. Only one patient with severe myelopathy due to extensive mixed-type OPLL developed a segmental weakness of the bilateral upper extremities. The overall fusion rate was 97%. Three patients with obvious spinal instability due to pseudarthrosis required reoperation. Of the graft materials used in this series, VB grafts were the most fragile.

Conclusions

The anterior approach is an effective route for decompressing the cervical cord with OPLL. Slight asymptomatic kyphotic deformity may be encountered. Of the graft materials used in our series, VB graft was considered most fragile, and thus least optimal.
Ophthalmological outcome following orbital resection in anterior and anterolateral skull base surgery
Authors: DeMonte Franco , Tabrizi Peyman , Culpepper Scott A. , Abi-Said Dima , Soparkar Charles N. S. , Patrinely James R.
Published: January 2008

Object

Partial resection of the orbital bones is not uncommon during the excision of anterior and anterolateral skull base tumors. Controversy exists regarding the need for and extent of the reconstruction necessary following this resection. The authors studied this factor in a series of patients.

Methods

The authors conducted a retrospective review of 56 patients in whom resection of 57 anterior or anterolateral skull base tumors and partial excision of the orbital bone were performed. Adverse ophthalmological outcomes were noted in 16 patients, in nine of whom adverse outcomes were believed to be directly related to resection of the orbital walls. Some degree of orbital reconstruction was performed during 23 of the 57 procedures. An adverse orbit-related outcome was strongly associated with resection of the orbital floor and with resection of two thirds or more of two or more orbital walls but not with the presence of absence or orbital reconstruction. The latter finding, however, is likely a function of selection bias.

Conclusions

In most patients after partial excision of the orbital bones, elaborate reconstruction is not necessary. Isolated medial and lateral orbital wall defects or combined superior and lateral orbital wall defects, especially in cases in which the periorbita is intact, probably do not require primary reconstruction. In cases of orbital floor defects, whether isolated or part of a multiple wall resection, primary reconstruction is recommended.
Meningiomas of the orbit: contemporary considerations
Authors: Boulos Paul T. , Dumont Aaron S. , Mandell James W. , Jane John A.
Published: January 2008

Meningiomas are the most frequently occurring benign intracranial neoplasms. Compared with other intracranial neoplasms they grow slowly, and they are potentially amenable to a complete surgical cure. They cause neurological compromise by direct compression of adjacent neural structures. Orbital meningiomas are interesting because of their location. They can compress the optic nerve, the intraorbital contents, the contents of the superior orbital fissure, the cavernous sinus, and frontal and temporal lobes. Because of its proximity to eloquent neurological structures, this lesion often poses a formidable operative challenge. Recent advances in techniques such as preoperative embolization and new modifications to surgical approaches allow surgeons to achieve their surgery-related goals and ultimately optimum patient outcome. Preoperative embolization may be effective in reducing intraoperative blood loss and in improving intraoperative visualization of the tumor by reducing the amount of blood obscuring the field and allowing unhurried microdissection. Advances in surgical techniques allow the surgeon to gain unfettered exposure of the tumor while minimizing the manipulation of neural structures. Recent advances in technology—namely, frameless computer-assisted image guidance—assist the surgeon in the safe resection of these tumors. Image guidance is particularly useful when resecting the osseous portion of the tumor because the tissue does not shift with respect to the calibration frame. The authors discuss their experience and review the contemporary literature concerning meningiomas of the orbit and the care of patients harboring such lesions.
Cranioorbital fibrous dysplasia: with emphasis on visual impairment and current surgical management
Authors: Dumont Aaron S. , Boulos Paul T. , Jane John A. , Ellegala Dilantha B. , Newman Steven A. , Jane John A.
Published: January 2008

Fibrous dysplasia is a benign but slowly progressive disorder of bone in which normal cancellous bone is replaced by immature woven bone and fibrous tissue. Significant deformity and both acute and chronic visual impairment can result. A contemporary understanding of fibrous dysplasia, emphasizing the origins of visual impairment, indications for decompressive surgery, and the techniques for correction of the cosmetic deformity are presented.

In their experience and review of the literature, the authors found the most frequent clinical presentations to be exophthalmos, displacement of the globe, abnormalities of extraocular motility, cosmetic deformity, and visual impairment. Although traditionally the cause of visual impairment has been ascribed to impingement of the optic canal on the optic nerve, the authors' experience is that the most common cause of visual loss is cystic degeneration of the tumor, particularly with those involving the anterior clinoid process. Exophthalmos and optic canal stenosis are less common causes of visual impairment. Indications for surgical intervention include acute and/or serially radiographically documented and relentless visual impairment and significant cosmetic deformity. Individualized management strategies are also discussed.
Resection of a dominant-hemisphere intraventricular meningioma facilitated by functional magnetic resonance imaging
Authors: Curry William T. , Cosgrove G. Rees , Buchbinder Bradley R. , Ojemann Robert G.
Published: January 2008

Intraventricular meningiomas of the lateral ventricle occur relatively rarely, but they are often large at the time of detection and present more commonly on the left side. Although the ability to resect these tumors safely has greatly improved over time, standard surgical approaches often traverse cortex close to areas of specific cortical function. Precise cortical mapping of language and sensorimotor cortices can be accomplished noninvasively by using functional magnetic resonance (fMR) imaging. The authors used fMR imaging in planning the cortical incision for resection of a large intraventricular trigone meningioma in the dominant hemisphere of a patient who, postoperatively, suffered no aphasia or hemiparesis. The authors discuss the advantages of mapping cortical function preoperatively with fMR imaging when approaching intraventricular lesions.