bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microendoscopic approach to far-lateral lumbar disc herniation
Authors: Foley Kevin T. , Smith Maurice M. , Rampersaud Y. Raja 
Published: January 2008

The purpose of this study was to determine the feasibility of performing far-lateral lumbar discectomy by using the microendoscopic discectomy (MED) technique. The authors studied 11 consecutive patients with unilateral, single-level radiculopathy secondary to far-lateral disc herniation. There were eight men and three women, with an average age of 43 years. In all patients magnetic resonance imaging and/or computerized tomography scanning documented far-lateral disc herniations. Six patients experienced motor deficits, nine patients sensory abnormalities, and five depressed reflexes. All patients complained of radicular pain, which failed to improve with conservative care.
After induction of epidural anesthesia, single-level, unilateral percutaneous discectomies were performed using the MED technique. Five discectomies were performed at L3-4 and six at L4-5. There were four contained and seven sequestered disc herniations. All surgeries were performed on an outpatient basis. Follow up ranged from for 12 to 27 months. Improvement was shown in all patients postoperatively. Using modified Macnab criteria to assess results of surgery, there were 10 excellent results and one good result. None of the patients experienced residual motor deficits, four had residual decreased sensation, and one still had some degree of nonradicular pain. There were no complications.
Although various open techniques exist for the treatment of far-lateral disc herniation, MED is unique in that far-lateral pathological entities can be directly visualized and removed via a 15-mm paramedian incision. The percutaneous approach avoids larger, potentially denervating and destabilizing procedures. The need for general anesthesia can be avoided, and surgery is performed on an outpatient basis, thereby reducing hospital cost and length of stay.
Posterior fusion and implantation of the SOCON-SRI system in the treatment of adult spondylolisthesis
Authors: La Rosa Giovanni , Germanò Antonino , Conti Alfredo , Cacciola Fabio , Caruso Gerardo , Tomasello Francesco 
Published: January 2008

Surgery for adult patients with lumbar and lumbosacral spondylolisthesis is reserved for those with intractable radiculopathy, claudication, or symptomatic spinal instability. Internal fixation, in which posterior fusion, transpedicular screw fixation, and implantation of titanium devices are performed, has been advocated to improve fusion rates and clinical results. Fourteen consecutive patients with Grade II to III lumbar and lumbosacral spondylolisthesis who underwent posterior decompression, reduction, autologous posterior facet joint arthrodesis, and SOCON-SRI implantation are retrospectively reviewed.
All patients underwent complete preoperative clinical and neuroradiological evaluation. Treatment consisted of posterior decompressive surgery and implantation of the SOCON-SRI system (transpedicular screws, prebent longitudinal rods, and one locking-screw clamps). Distraction of the interbody space and rotation were performed to achieve an optimum spinal realignment. The facet joints were fused by using autologous bone graft. The authors obtained detailed clinical, functional, economic, and neuroradiological follow-up data for up to 14 months (range 8–18 months).
The efficacy of the treatment was evaluated by comparing pre- and postoperative data. Pain was decreased in all cases, neurological dysfunction ameliorated in 50%, and functional and economic status was improved in 78% and 100%, respectively. No cases of fusion failure or instrumentation-related complications occurred. The authors describe their results of treating patients with spondylolisthesis in the light of the rationale for surgery and the more recent pertinent literature.
Lumbosacral junction fixation and fusion after complete L-5 spondylectomy
Authors: Detwiler Paul W. , Porter Randall W. , Crawford Neil R. , Apostolides Paul J. , Dickman Curtis A. 
Published: January 2008

The goals of surgery for metastatic disease of the lumbosacral spine are to relieve compression of the thecal sac and nerve roots, to resect malignant tissue, and to create a stable reconstruction of the spine. Reconstruction of the lumbosacral junction, specifically the L-5 vertebral body, is particularly challenging because the biomechanical properties of this level differ from other areas of the spine.
A 40-year-old woman with intraductal breast carcinoma that metastasized to the L-5 vertebral body presented with progressive low-back pain, right-sided L-5 radiculopathy, and weakness. Magnetic resonance imaging revealed a pathological fracture of the L-5 vertebral body with compression of the cauda equina. The L-5 posterior arch, both facet joints and pedicles, and the posterior third of the vertebral body were removed via a posterior approach. A pedicle screw fixation system was applied from L-4 to S-1. The patient was repositioned, and a transabdominal approach was used to resect the anterior two thirds of the L-5 body, which was reconstructed using an allograft bone strut. An interference bone screw was placed through the inferior aspect of the allograft and screwed into the body of S-1 to provide stability for the reconstructive graft.
The patient's clinical recovery was excellent. She was ambulating without difficulty when seen at 19-month follow-up examination.
Complete spondylectomy by using this novel fusion technique was efficacious in the treatment of metastatic disease to the vertebral column.
Stabilizing effect of posterior lumbar interbody fusion cages before and after cyclic loading
Authors: Kettler Annette , Wilke Hans-Joachim , Dietl Rupert , Krammer Matthias , Lumenta Christianto , Claes Lutz 
Published: January 2008

The function of interbody fusion cages is to stabilize spinal segments primarily by distracting them as well as by allowing bone ingrowth and fusion. An important condition for efficient formation of bone tissue is achieving adequate spinal stability. However, the initial stability may be reduced due to repeated movements of the spine during everyday activity. Therefore, in addition to immediate stability, stability after cyclic loading is of remarkable relevance; however, this has not yet been investigated. The object of this study was to investigate the immediate stabilizing effect of three different posterior lumbar interbody fusion cages and to clarify the effect of cyclic loading on the stabilization.
Before and directly after implantation of a Zientek, Stryker, or Ray posterior lumbar interbody fusion cage, 24 lumbar spine segment specimens were each evaluated in a spine tester. Pure lateral bending, flexion-extension, and axial rotation moments (± 7.5 Nm) were applied continuously. The motion in each specimen was measured simultaneously. The specimens were then loaded cyclically (40,000 cycles, 5 Hz) with an axial compression force ranging from 200 to 1000 N. Finally, they were tested once again in the spine tester.
In general, a decrease of movement in all loading directions was noted after insertion of the Zientek and Ray cages and an increase of movement after implantation of a Stryker cage. In all three cage groups greater stability was demonstrated in lateral bending and flexion than in extension and axial rotation. Reduced stability during cyclic loading was observed in all three cage groups; however, loss of stability was most pronounced when the Ray cage was used.
Outcome prediction following penetrating craniocerebral injury in a civilian population: aggressive surgical management in patients with admission Glasgow Coma Scale scores of 6 to 15
Authors: Levy Michael L. 
Published: January 2008

In an attempt to assess admission Glasgow Coma Scale (GCS) scores and other radiographic variables after penetrating craniocerebral injury in relationship to outcome, the author evaluated a series of 294 patients with penetrating injuries who presented with a GCS score of 6 to 15 over a 6-year period. Entrance criteria required a replicable neurological examination that was not altered by the presence of hypotension, drugs/toxins, or systemic injury. All patients underwent surgical intervention and aggressive perioperative management, including resuscitative protocols, in the neurosurgical intensive care unit.
The author previously devised prospective models of outcome remained unchanged in this series. The variables most predictive of death include admission GCS score and subarachnoid hemorrhage in one model and admission GCS score and pupillary changes in a second when pupillary response was definitive at admission (p ≤ 0.00005). Other important variables related to morbidity include admission GCS, bihemispheric injury when associated with intraventricular hemorrhage, and diffuse fragmentation (p ≤ 0.001).
In this study a significant relationship between operative intervention and survival (p ≤ 0.01) was found in patients with an admission GCS scores of 6 to 8. No significant relationships between operative intervention and survival were found in patients with admission GCS scores of 9 to 12 and 13 to 15. A significant relationship between operative intervention and morbidity (p ≤ 0.01) was also demonstrated in patients with an admission GCS score of 12 to 15. No significant relationships between operative intervention and morbidity were found in patients with an admission GCS score of 6 to 8 and 9 to 12.
Activation of the anterior cingulate cortex by thalamic stimulation in patients with chronic pain: a positron emission tomography study
Authors: Davis Karen D. , Taub Ethan , Duffner Frank , Lozano Andres M. , Tasker Ronald R. , Houle Sylvain , Dostrovsky Jonathan O. 
Published: January 2008

Object
Deep brain stimulation (DBS) of the sensory thalamus has been used to treat chronic, intractable pain. The goal of this study was to investigate the thalamocortical pathways activated during thalamic DBS.

Methods
The authors compared positron emission tomography (PET) images obtained before, during, and after DBS in five patients with chronic pain. Two of the five patients reported significant DBS-induced pain relief during PET scanning, and the remaining three patients did not report any analgesic effect of DBS during scanning. The most robust effect associated with DBS was activation of the anterior cingulate cortex (ACC). An anterior ACC activation was sustained throughout the 40 minutes of DBS, whereas a more posteriorly located ACC activation occurred at a delay after onset of DBS, although these activations were not dependent on the degree of pain relief reported during DBS. However, implications specific to the analgesic effect of DBS require further study of a larger, more homogeneous patient population. Additional effects of thalamic DBS were detected in motor-related regions (the globus pallidus, cortical area 4, and the cerebellum) and visual and association cortical areas.

Conclusions
The authors demonstrate that the ACC is activated during thalamic DBS in patients with chronic pain.
A positron emission tomography study of cerebrovascular reserve before and after shunt surgery in patients with idiopathic chronic hydrocephalus
Authors: Klinge Petra M. , Berding Georg , Brinker Thomas , Knapp Wolfram H. , Samii Madjid 
Published: January 2008

Object
In this study the authors use positron emission tomography (PET) to investigate cerebral blood flow (CBF) and cerebrovascular reserve (CVR) in chronic hydrocephalus.

Methods
Ten patients whose mean age was 67 ± 10 years (mean ± standard deviation [SD]) were compared with 10 healthy volunteers who were 25 ±3 years of age. Global CBF and CVR were determined using 15O–H2O and PET prior to shunt placement and 7 days and 7 months thereafter. The CVR was measured using 1 g acetazolamide. Neurological status was assessed based on a score assigned according to the methods of Stein and Langfitt.
Seven months after shunt placement, five patients showed clinical improvement (Group A) and five did not (Group B). The average global CBF before shunt deployment was significantly reduced in comparison with the control group (40 ± 8 compared with 61 ± 7 ml/100 ml/minute; mean ± SD, p < 0.01). In Group A the CBF values were significantly lower than in Group B (36 ± 7 compared with 44 ± 8 ml/100 ml/minute; p < 0.05). The CVR before surgery, however, was not significantly different between groups (Group A = 43 ± 21%, Group B = 37 ± 29%). After shunt placement, there was an increase in the CVR in Group A to 52 ± 37% after 7 days and to 68 ± 47% after 7 months (p < 0.05), whereas in Group B the CVR decreased to 14 ± 18% (p < 0.05) after 7 days and returned to the preoperative level (39 ± 6%) 7 months after shunt placement.

Conclusions
The preliminary results indicate that a reduced baseline CBF before surgery does not indicate a poor prognosis. Baseline CBF before shunt placement and preoperative CVR are not predictive of clinical outcome. A decrease in the CVR early after shunt placement, however, is related to poor late clinical outcome, whereas early improvement in the CVR after shunt placement indicates a good prognosis.
Hypoxia-inducible expression of BAX: application in tumor-targeted gene therapy
Authors: Ruan Hangjun , Hu Lily , Wang Jingli , Ozawa Tomoko , Sanai Nader , Zhang Michael , Lamborn Kathleen R. , Deen Dennis F. 
Published: January 2008

Object
The presence of hypoxic cells in human brain tumors contributes to the resistance of these tumors to radiation therapy. However, because normal tissues are not hypoxic, the presence of hypoxic cells also provides the potential for designing cancer-specific gene therapy. Suicide genes can be expressed specifically in hypoxic conditions by hypoxia-responsive elements (HREs), which are activated through the transcriptional complex hypoxia-inducible factor–1 (HIF-1).

Methods
The authors have transfected the murine BAX–green fluorescent protein (GFP) fusion gene under the regulation of three copies of HRE into U-87 MG and U-251 MG cells and selected stably transfected clones. Even though BAX was expressed under both oxic and anoxic conditions in these clones, cell survival assays demonstrated increased cell killing under anoxic as compared with oxic conditions. Cells obtained from most of these clones did not grow in vivo, or the tumors exhibited highly variable growth rates. However, cells obtained from the U-251 MG clone A produced tumors that grew as well as tumors derived from parental cells, and examination of the tumor sections under fluorescent microscopy revealed GFP expression in localized regions. Western blot analyses confirmed an increased BAX expression in these tumors. Analysis of the results suggests that HRE-regulated BAX can be a promising tool to target hypoxic brain tumor cells. However, there are measurable levels of BAX-GFP expression in this three-copy HRE–mediated expression system under oxia, suggesting promoter leakage. In addition, most clones did not show significant induction of BAX-GFP under anoxia. Therefore, the parameters of this HRE-mediated expression system, including HRE copy number and the basal promoter, need to be optimized to produce preferential and predictable gene expression in hypoxic cells.
Direct anterior screw fixation for recent and remote odontoid fractures
Authors: Apfelbaum Ronald I. , Lonser Russell R. , Veres Robert , Casey Adrian 
Published: January 2008

Object
The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1–2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions.

Methods
One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for a recent fracture (< 6 months postinjury [129 patients]) or remote (≥ 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow-up period 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients.
In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p ≤ 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (as compared with anterior oblique), but this finding was independent (p ≥ 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and unrelated to hardware in three patients (2%). There was one death (1%) related to surgery.

Conclusions
Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (< 6 months postinjury). It confers immediate stability, preserves C1–2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (≥ 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.
Management of acute odontoid fractures: operative techniques and complication avoidance
Authors: SK Shushil Shilpakar , McLaughlin Mark R. , Haid Regis W. , Rodts Gerald E. , Subach Brian R. 
Published: January 2008

In this article the authors describe the management of Type II odontoid fractures with special attention to operative technique and avoidance of complication. Anterior odontoid screw fixation is a procedure the authors have performed over the last 8 years in cases with acute Type II and rostral Type III odontoid fractures. In cases of Chronic Type II odontoid fractures and in patients with transverse ligament disruption, the authors prefer to undertake posterior transarticular facet screw fixation supplemented by bone graft and interspinous C1–2 wiring.
The technical aspects of these procedures are described with a focus on operative nuances. Selection criteria and techniques that the authors have refined over the years have helped them to optimize success rates and minimize complications.
Persistent posttraumatic cerebrospinal fluid leakage
Authors: Friedman Jonathan A. , Ebersold Michael J. , Quast Lynn M. 
Published: January 2008

Object
Persistent posttraumatic cerebrospinal fluid (CSF) leakage frequently complicates skull base fractures. Although many CSF leaks will cease without treatment, patients with CSF leaks that persist greater than 24 hours may be at increased risk for meningitis, and many will require surgical intervention. The authors reviewed their 15-year experience with posttraumatic CSF leaks that persisted longer than 24 hours.

Methods
The authors reviewed the medical records of 51 patients treated between 1984 and 1998 with CSF leaks that persisted for 24 hours or longer after traumatic head injury. In 27 patients (55%) spontaneous resolution of CSF leakage occurred at an average of 5 days posttrauma. In 23 patients (45%) surgery was required to resolve the leakage. Eight patients (16%) with occult CSF leaks presented with recurrent meningitis at an average of 6.5 years post-trauma. Forty-three (84%) patients with CSF leaks sustained a skull fracture, most commonly involving the frontal sinus, whereas parenchymal brain injury or extraaxial hematoma was demonstrated in only 18 patients (35%). Delayed CSF leaks, with an average onset of 13 days posttrauma, were observed in eight patients (16%).
Among patients with clinically evident CSF leakage, the frequency of meningitis was 10% with antibiotic prophylaxis, and 21% without antibiotic prophylaxis. Thus, prophylactic antibiotic administration halved the risk of meningitis. A variety of surgical approaches was used, and no significant neurological morbidity occurred. Three (13%) of 23 surgically treated patients required additional surgery to treat continued CSF leakage.

Conclusions
A significant proportion of patients with CSF leaks that persist greater than 24 hours will require surgical intervention. Prophylactic antibiotic therapy may be effective in this group of patients. Patients with skull base or frontal sinus fractures should be followed to detect the occurrence of delayed leakage. Surgery-related outcome is excellent.
The role of radiosurgery for multiple brain metastases
Authors: Cho Kwan H. , Hall Walter A. , Gerbi Bruce J. , Higgins Patrick D. 
Published: January 2008

Object
The authors evaluated the role of stereotactic radiosurgery (SRS) in patients with multiple brain metastases by analyzing prognostic factors that predict survival.

Methods
Between March 1991 and January 1999, 83 patients with multiple brain metastases underwent SRS in which they used a 6 mV linear accelerator. The median radiation dose of 15 Gy (range 6–50 Gy) was delivered to the 40 to 90% (median 87%) isodose line encompassing the target. Actuarial overall survival was calculated from the date of SRS by using the Kaplan–Meier method. Univariate comparisons of survival between different groups were performed using a log-rank test. All 83 patients were included in the calculation of overall survival. Actuarial overall survival was 22% at 1 year and 13% at 2 years, and a median survival of 5.4 months (range, 0.3–28.8 months) was demonstrated. Variables that predicted survival were Karnofsky Performance Scale (KPS) score, extracranial disease status, and the number of intracranial metastases. Median survival in patients with a KPS score greater than as compared with less than 70 was 9.1 and 2.7 months, respectively (p = 0.002). Median survival when comparing absence and presence of extracranial disease was 9.9 and 4.1 months, respectively (p = 0.02). Median survival in patients harboring two, three, or four or more lesions was 6.6 months, 5.4 months, and 2.7 months, respectively (p = 0.02). In patients with a KPS score greater than or equal to 70 and with three or fewer lesions, median survival was 7 months or longer. In patients with four or more lesions median survival was 7.4 months for those with no extracranial disease and 2.4 months for those with extracranial disease. Other variables tested (sex, histological tumor type, previous resection, location of metastases, treatment modality, and tumor status) did not influence outcome.

Conclusions
The absence of extracranial disease, a KPS score greater than or equal to 70, and fewer number of metastases were shown to be significant predictors of longer survival. Stereotactic radiosurgery appears to be a reasonable therapeutic option in patients with up to three lesions when their KPS score is greater than or equal to 70, regardless of extracranial disease status. In those with four or more metastases, however, SRS should be limited to those with no extracranial disease.