bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic motor evoked potential monitoring in the rat
Authors: Linden R. Dean , Zhang Yi-Ping , Burke Darlene A. , Hunt Matthew A. , Harpring John E. , Shields Christopher B. 
Published: May 2009

Object. The authors conducted a study to provide an objective electrophysiological assessment of descending motor pathways in rats, which may become a means for predicting outcome in spinal cord injury research.
Methods. Transcranial magnetic motor evoked potentials (TMMEPs) were recorded under various conditions in awake, nonanesthetized, restrained rats. Normative data were collected to determine the reproducibility of the model and to evaluate the effect of changing the stimulus intensity on the evoked signals. In addition, an experiment was performed to determine if the TMMEPs produced were the result of auditory startle response (ASR) potentials elicited by the sound generated by the movement of the copper coil inside its casing during magnetic stimulation.
Transcranial magnetic motor evoked potentials were elicited after magnetic stimulation. At 100% stimulus intensity, the mean forelimb onset latency was 4.2 ± 0.39 msec, and the amplitude was 9.16 ± 3.44 mV. The hindlimb onset latency was 6.5 ± 0.47 msec, and the amplitude was 11.47 ± 5.25 mV. As the stimulus intensity was decreased, the TMMEP onset latency increased and the response amplitude decreased. The ASR potentials were shown to have longer latencies, smaller amplitudes, and were more variable than those of the TMMEPs.
Conclusions. These experiments demonstrate that TMMEPs can be recorded in awake, nonanesthetized rats. The evoked signals were easy to elicit and reproduce. This paper introduces noninvasive TMMEPs as a new technique for monitoring the physiological integrity of the rat spinal cord.
Surgically treated lumbar disc disease in the pediatric population: an outcome study
Authors: Durham Susan R. , Sun Peter P. , Sutton Leslie N. 
Published: May 2009

Object. This outcome study was undertaken to investigate the long-term results obtained in surgically treated pediatric patients with lumbar disc disease by using standardized medical outcome scales and clinical follow-up examination.
Methods. Twenty nine patients 17 years of age or younger underwent surgery between 1968 and 1998 for lumbar disc disease. The follow-up period ranged from 4 months to 30.5 years (mean 8.5 years). Outcome scores (health profiles) were generated using a standardized medical outcome scale, the Short Form health survey questionnaire (SF-36), and a condition-specific back pain outcome scale. Clinical follow-up data were obtained by telephone interview.
The health profile of the study population closely paralleled that of the normal population and was distinctly different from the health profile of adults with low-back pain. Only physical functioning, as measured by a scale of the SF-36, was found to be impaired in a subset of the study population. The rate of reoperation was 24% over the course of the follow-up period. In contrast to similar studies in adults, there were no identifiable predictive factors for either reoperation or poor outcome.
Conclusions. Lumbar disc disease in the pediatric population does not appear to lead to chronic complaints of back pain, and it does not appear to have a negative impact on overall health. This finding suggests that pediatric lumbar disc disease may be a separate entity distinct from adult lumbar disc disease, and therefore, the same conclusions regarding long-term outcome cannot be applied to the pediatric population.
Anatomical suitability of C1–2 transarticular screw placement in pediatric patients
Authors: Brockmeyer Douglas L. , York Julie E. , Apfelbaum Ronald I. 
Published: May 2009

Object. Craniovertebral instability is a challenging problem in pediatric spinal surgery. Recently, C1–2 transarticular screw fixation has been used to assist in craniovertebral joint stabilization in pediatric patients. Currently there are no available data that define the anatomical suitability of this technique in the pediatric population. The authors report their experience in treating 31 pediatric patients with craniovertebral instability by using C1–2 transarticular screws.
Methods. From March 1992 to October 1998, 31 patients who were 16 years of age or younger with atlantooccipital or atlantoaxial instability, or both, were evaluated at our institution. There were 21 boys and 10 girls. Their ages ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (eight patients). Six patients had undergone a total of nine previous attempts at posterior fusion while at outside institutions.
All patients underwent extensive preoperative radiological evaluation including fine-slice (1-mm) computerized tomography scanning with multiplanar reconstruction to evaluate the anatomy of the C1–2 joint space. Preoperatively, of the 62 possible C1–2 joint spaces in 31 patients, 55 sides (89%) were considered suitable for transarticular screw placement. In three patients the anatomy was considered unsuitable for bilateral screw placement. In three patients the anatomy was considered inadequate on one side. Fifty-five C1–2 transarticular screws were subsequently placed, and there were no neurological or vascular complications.
Conclusions. The authors conclude that C1–2 transarticular screw fixation is technically possible in a large proportion of pediatric patients with craniovertebral instability.
Fusion and instrumentation at C1–3 via the high anterior cervical approach
Authors: Vender John R. , Harrison Steven J. , McDonnell Dennis E. 
Published: May 2009

Object. The high anterior cervical, retropharyngeal approach to the anterior foramen magnum and upper cervical spine is a favorable alternative to the transoral and posterolateral approaches, which both cause instability of the craniovertebral junction. Previously, such instability was corrected via an occipitocervical fusion during a separate surgical procedure.
Methods. Seven patients requiring C-2 corpectomy (foramen magnum meningioma [two patients], critical stenosis secondary to rheumatoid arthritis [two patients], C-2 fracture [two patients], and stenosis secondary to Rickets [one patient]) are presented. All patients underwent C1–3 fusion followed by instrumentation with a Caspar plate. A solid fusion was achieved in six patients. One patient experienced erosion of the anterior arch of C-1 requiring posterior stabilization.
Conclusions. Fusion and instrumentation at C1–3 can be performed safely and with minimal increase in surgical time. In selected patients, this may eliminate the need for an additional posterior procedure and maintain occipital—C1 mobility.
Indirect posterior reduction and fusion of the traumatic herniated disc by using a cervical pedicle screw system
Authors: Abumi Kuniyoshi , Shono Yasuhiro , Kotani Yoshihisa , Kaneda Kiyoshi 
Published: May 2009

Object. In this study the authors retrospectively review 16 patients with traumatic disc herniation secondary to middle and lower cervical spine injuries who underwent a single posterior reduction and fusion procedure in which a cervical pedicle screw system was used. The study was undertaken to evaluate whether the procedure effectively reduced the disc herniation and whether it can be safely conducted without performing anterior decompressive surgery.
Methods. A total of 73 patients with middle and lower cervical spine injuries were identified. In 50 patients, pre- and postoperative magnetic resonance (MR) images were obtained, and disc herniation was defined as the presence of an extruded disc that deformed the thecal sac or nerve roots. Traumatic disc herniation was revealed in 16 patients (32%) who underwent a single posterior reduction/fusion procedure in which a cervical pedicle screw system was used. The average follow-up period was 4.25 years (2–6.25 years). In all patients the average kyphotic deformity was 18°, which was corrected to 0.7° lordosis postoperatively. Anterior translation was reduced from 8 to 0.7 mm. The preoperative disc height ratio of 63% (normal 100%) was improved to 104%. Preoperative MR images revealed traumatic disc herniation in all 16 patients; postsurgery, reduction or reversal of disc herniation was observed in all patients. Thecal sac and/or spinal cord compression had disappeared after indirect decompression was achieved using a posterior procedure. No additional decompressive procedures were required to remove residual herniated disc material. Preoperatively, four patients presented with cervical radiculopathy, 10 with myelopathy (eight incomplete and two complete), and two without neurological symptoms. At final follow up, complete recovery was observed in all four patients with radiculopathy and improvement of at least one Frankel grade was shown in six patients (60%) with myelopathy. There were no cases of neurological deterioration immediately after surgery or during the course of the follow-up period. In all patients solid bone union was demonstrated, and there were no implant-related complications.
Conclusions. Traumatic disc herniation may occur frequently in association with injury of the cervical spine. The incidence of traumatic disc herniation in our series was 32%. The cervical pedicle screw system allowed three-dimensional reduction of the injured cervical segment and reduction or reversal of a disc herniation. After surgery, compression of the thecal sac and/or spinal cord had disappeared. The cervical pedicle screw system provides effective and safe fixation of the cervical spine injury—related traumatic disc herniation, and the surgery can be performed safely in a single posteriorapproach procedure without need of additional anterior decompressive interventions.
Open-door laminoplasty for cervical stenotic myelopathy: surgical technique and neurophysiological monitoring
Authors: Roselli Romeo , Pompucci Angelo , Formica Francesco , Restuccia Domenico , Di Lazzaro Vincenzo , Valeriani Massimiliano , Scerrati Massimo 
Published: May 2009

Object. A modified technique of open-door laminoplasty for cervical stenotic myelopathy (CSM) is described, and the role of evoked potential monitoring in selecting patients for surgery and evaluating results is discussed.
Methods. Between October 1992 and October 1996, 33 patients with CSM underwent open-door laminoplasty. After surgery, in 27 patients (81.8%) different levels of clinical improvement were demonstrated, and in five of them (15%) full recovery was observed. The Japanese Orthopaedic Association score increased from 5 to 12 (mean 9.8) preoperatively to 8 to 14 (mean 11.6) postoperatively. At 1-year follow up, the N13 cervical response was restored in nine (75%) of 12 patients with isolated presurgical abnormality and in 57.1% of those with combined abnormalities of both N13 and P14 response. Although significant clinical improvement was observed in 82% of the cases, in 24 of 33 patients MEP abnormalities persisted at least at one explored level.
Conclusions. Of several laminoplasty techniques, the one described here offers some advantages: preservation of biomechanical function of posterior muscular—ligamentous complex, prevention of laminar collapse, smaller degrees in reduction of range of cervical motion, stabilization of the spine with no postoperative malalignment, and maintenance of decompressive effect that avoids recurrent stenosis. Neurophysiological studies sometimes clarified neurological disorders that were only suspected on the basis of history and/or clinical examination, leading to early diagnosis.
Changes of bilateral palmar skin temperature in transthoracic endoscopic T-2 sympathectomy
Authors: Lu Kang , Liang Cheng-Loong , Lee Tao-Chen , Chen Han-Jung , Su Thung-Ming , Liliang Po-Chou 
Published: May 2009

Object. Transthoracic endoscopic T-2 sympathectomy is currently the treatment of choice for palmar hyperhidrosis (PH). Intraoperative monitoring of palmar skin temperature (PST) is often used to assess the adequacy of sympathetic ablation. The aim of this study was to investigate the time course of PST changes during the operation and to determine factors involved in the sympathetic modulation of the palmar skin blood flow.
Methods. Eighty-one patients with PH underwent bilateral transthoracic endoscopic sympathectomy of T-2 in which continuous intraoperative PST monitoring was used. Palmar skin temperature data, recorded every 30 seconds throughout the operation, were plotted against time, and a graph of two PST curves was obtained in each case. A multiphasic curve pattern of great similarity was observed in nearly 70% of cases. Specific PST readings at different operative stages were collected and averaged for all cases. The trend of PST changes in response to different procedures during the operation was analyzed.
It was found that unilateral procedures caused simultaneous bilateral PST alterations. In almost all cases, bilateral PST was dramatically lowered when unilateral skin incision and intercostal muscle dissection were performed. The temperature remained low until the T-2 sympathectomy was finished on one side. In addition, unilateral T-2 sympathectomy induced synchronous elevation of bilateral PST. However, the ipsilateral response was significantly stronger than that on the contralateral side.
Conclusions. Although intraoperative monitoring of PST is a reliable guide for surgeons performing endoscopic transthoracic sympathectomy, it is important to realize that PST fluctuates at different stages during the operation and that surgical procedures themselves can significantly influence PST readings. The PST data recorded at specific time points, therefore, can be misleading in terms of accuracy and the completeness of ablation of the target sympathetic ganglia, especially when the sympathetic trunk or ganglia are anatomically aberrant.
Ventral foramen magnum meningiomas
Authors: Arnautović Kenan I. , Al-Mefty Ossama , Husain Muhammad 
Published: May 2009

Object. Ventral foramen magnum meningiomas (VFMMs) are rare lesions that account for more than 3% of all meningiomas. These are among the most challenging of all meningiomas to treat. The authors comprehensively analyzed multiple features in a series of VFMMs.
Methods. A retrospective study was performed of 18 patients who harbored a meningioma in the ventral foramen magnum (mean follow-up period, 40 months) and underwent surgery via a transcondylar approach. Sixteen patients underwent surgery for the first time: 12 underwent gross-total (75%), two near-total (12.5%), and two subtotal (12.5%) tumor removal. The remaining two patients were treated for a recurrent tumor. After obtaining postoperative Karnofsky Performance Scale (KPS) scores at follow up, statistically significant improvement was demonstrated compared with the preoperative scores. The extent of surgery and higher preoperative KPS scores were variables that showed statistically significant favorable influence on outcome. Ninth and 10th cranial nerve deficits were the most common complications contributing to a prolonged hospital stay. There were no perioperative deaths. Four patients died during the follow-up period. The first patient died of multiple myeloma. The second patient, in whom surgery was performed to treat a recurrent tumor, died 3 years after the surgery of new tumor recurrence at the age of 80 years. The remaining two patients died 1.5 and 5 months postsurgery of pulmonary embolus and endocarditis, respectively.
Conclusions. Ventral foramen magnum meningiomas can be radically resected in a majority of patients, with frequent but transient morbidity caused by lower cranial nerve deficits. Radical removal of a recurrent tumor provides a relatively long, stable postoperative course. In patients presenting with a low KPS score a poor prognosis is demonstrated, and early diagnosis and treatment are recommended to avoid it.
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: May 2009

Object. 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.
Methods. 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.
Conclusions. 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.
Retrieval of broken pedicle screws by “friction” technique
Authors: Di Lorenzo Nicola , Conti Renato , Romoli Stefano 
Published: May 2009

U The authors describe a simple and fast technique for removal of deeply situated broken pedicle screw fragments.
The screw fragments are removed using a fine-serrated, conically cored bit with a light rough inner surface that is mounted on a common slow-speed drill capable of rotating clockwise and counterclockwise. The cored head of the bit is pressed and engaged on the cut surface of the broken screw, and the drill is made to turn in counterclockwise rotation; this, by means of friction, causes the two surfaces to interlock, and consequently the broken screw fragment backs out. This technique was used to retrieve both broken titanium and stainless steel screws, and satisfying results were obtained. There were no complications associated with the application of the technique, and the pedicle as well as the screw hole were always preserved, offering, in the event that the vertebral instability continued, the possibility of applying a new screw of slightly larger diameter at the same screw hole.
This technical application offers the opportunity of removing deeply situated screw fragments by using a simple technique while maintaining the vertebral pedicle and screw-hole integrity.
Duration of leg pain as a predictor of outcome after surgery for lumbar disc herniation: a prospective cohort study with 1-year follow up
Authors: Nygaard Øystein P. , Kloster Roar , Solberg Tore 
Published: May 2009

Object. The aim of this study was to investigate different variables in the duration of symptoms that can be used to predict outcome after lumbar microdiscectomy.
Methods. In a prospective study of 132 consecutive patients who underwent surgery for lumbar disc herniation, the authors evaluated the prognostic value of different variables in the duration of symptoms for the 1-year period after surgery. The 1-year follow-up investigation was conducted by an independent observer. Assessment of outcome was performed using a clinical overall score (COS), which was recently assessed for its reliability and validity. As for factors predictive of outcome, only duration of leg pain and sick leave reached statistical significance in the multivariate analysis. Results of the univariate analysis demonstrated that in patients experiencing preoperative leg pain fewer than 4 months and between 4 and 8 months, a significantly lower COS at the 1-year follow up was demonstrated compared with those in whom the duration of leg pain was longer (> 8 months). One hundred eight patients returned to work within the 1st year after surgery. Patients who took a sick leave of more than 28 weeks before the operation were at higher risk of not returning to work.
Conclusions. Analysis of these results indicates that leg pain lasting more than 8 months correlates with an unfavorable postoperative outcome in patients with lumbar disc herniation, as well as a high risk of not returning to work.
Pathoanatomy of clinical findings in patients with sciatica: a magnetic resonance imaging study
Authors: Vroomen Patrick C. A. J. , de Krom Marc C. T. F. M. , Wilmink Jan T. 
Published: May 2009

Object. Anatomical details of nerve root compression may explain the production of the signs and symptoms of sciatica. The authors of anatomical studies have offered many theories without clearly demonstrating the clinical relevance of the observations. Clinicoanatomical series are scarce and are affected to a great extent by selection bias.
Methods. We created a schematic drawing of the lumbar anatomy based on both the literature and in vitro anatomical observations. A diagnosis was then made with the aid of detailed and standardized clinical and magnetic resonance (MR) imaging studies in primary-care patients who presented with pain that radiated into the leg. Clinical and MR imaging findings were correlated. Finally, the anatomical drawing was compared with the clinical data.
The higher the vertebral level of symptomatic disc herniations, the more likely the compression will be more laterally situated. Classic symptoms of sciatica (typically, dermatomal pain; increase in pain when coughing, sneezing, or straining; and testing positive for pain during straight leg raising) were most likely to occur with compression of the nerve root in the axilla and with mediolateral disc herniations.
Conclusions. The L-3, L-4, L-5, and S-1 nerve roots each tend to be compressed at different sites along the rostrocaudal course of the nerve root. Disc herniations become symptomatic at different sites for each disc level. The schematic drawing produced a priori could well be used to explain these findings. Expectations of particular clinical findings can be predicted by specific pathoanatomical findings.