Sacroiliac Joint Fusion-A Shift Toward Variant Anatomy and Clinical Implications.

OBJECTIVE: To investigate impact of patient factors and sacroiliac joint (SIJ) anatomical structure on SIJ fusion outcomes. METHODS: This single-center, retrospective, observational study evaluated patients diagnosed with SIJ dysfunction refractory to conservative measures who had available preoperative imaging of the sacrum and underwent SIJ fusion surgery. The impact of patient sociodemographics on pain improvement was assessed by Mann-Whitney U test. Differences in patient sociodemographics and outcome information between anatomical subtypes were assessed with χ2 and Kruskal-Wallis tests. χ2 test was used to compare joint anatomy distribution between studies analyzing SIJ variations. RESULTS: We included 77 total joints that underwent instrumentation. There were significant differences between the anatomical subtypes with female sex having significantly higher rates of non-normal joint anatomy. Younger age was significantly more common in bipartite/dysmorphic anatomy (53.9 years) than normal anatomy (70 years) (P < 0.05). There was a trend toward better outcomes in bipartite/dysmorphic and accessory variants, while semicircular defect and crescent variants trended toward worse outcomes. Nonnormal anatomy was significantly more frequent in our population than previous reports on nonpathological SIJ. CONCLUSIONS: A pathological SIJ has a significantly higher prevalence of variant joint anatomy. There appears to be a trend toward differences in surgical outcomes based on SIJ anatomy. Future research with larger sample sizes is necessary to confirm these differences.

The Feasibility of Translaminar Screws in the Subaxial Cervical Spine: Computed Tomography and Cadaveric Validation.

BACKGROUND: The use of translaminar screws may serve as a viable salvage method for complicated cases. To our understanding, the study of the feasibility of translaminar screw insertion in the actual entire subaxial cervical spine has not been carried out yet. The purpose of this study was to report the feasibility of translaminar screw insertion in the entire subaxial cervical spine. METHODS: Eighteen cadaveric spines were harvested from C3 to C7 and 1-mm computed tomography (CT) scans and three-dimensional reconstructions were created to exclude any bony anomaly. Thirty anatomically intact segments were collected (C3, 2; C4, 3; C5, 3; C6, 8; and C7, 14), and randomly arranged. Twenty-one segments were physically separated at each vertebral level (group S), while 9 segments were not separated from the vertebral column and left in situ (group N-S). CT measurement of lamina thickness was done for both group S and group N-S, and manual measurement of various length and angle was done for group S only. Using the trajectory proposed by the previous studies, translaminar screws were placed at each level. Screw diameter was the same or 0.5 mm larger than the proposed diameter based on CT measurement. Post-insertion CT was performed. Cortical breakage was checked either visually or by CT. RESULTS: When 1° and 2° screws of the same size were used, medial cortex breakage was found 13% and 33% of the time, respectively. C7 was relatively safer than the other levels. With larger-sized screws, medial cortex breakage was found in 47% and 46% of 1° and 2° screws, respectively. There were no facet injuries due to the screws in group N-S. CONCLUSIONS: Translaminar screw insertion in the subaxial cervical spine is feasible only when the lamina is thick enough to avoid any breakage that could lead to further complications. The authors do not recommend inserting translaminar screws in the subaxial cervical spine except in some salvage cases in the presence of a thick lamina.

Anatomy of Lamina in the Subaxial Cervical Spine With the Special Reference to Translaminar Screws: CT and Cadaveric Analysis With Screw Trajectory Simulation.

STUDY DESIGN: A cadaveric study. SUMMARY OF BACKGROUND DATA: Translaminar screws were initially developed for C2 fixation. Since then, their usage has expanded to include the subaxial cervical spine, and thoracic and lumbar spine. To the best of our knowledge, special anatomy for inserting translaminar screws in the subaxial cervical spine has not been studied. OBJECTIVE: To report the special anatomy for inserting translaminar screws in the subaxial cervical spine. METHODS: A total of 18 cadaveric spines were harvested from C3 to C7 and 1 mm computed tomography (CT) scans and 3D reconstructions were obtained. Bilateral translaminar screw entry points and trajectories were simulated at each level from C3 to C7 utilizing Kodak Carestream/Pacs Ver 10.2. Constructs were selected to achieve maximal bony purchase with 1 screw, designated the "primary screw." The contralateral screw, designated the "secondary screw," was selected to achieve the optimal allowable diameter possible while avoiding a simulated cortical breach, which was not always necessarily the "best purchase" diameter. Initial screw diameters selected were 3.5 mm; however, in the event that a narrower portion was encountered, then a 3.0 mm diameter screw was utilized instead. The crossing area of both screws were calculated geometrically. Maximal thickness of the lamina was considered in determining the diameter of screws. Whenever possible, 3.5 mm screws were selected in both lamina (3.5/3.5 mm); however, if a 3.5 mm screw was utilized as the primary screw, but the permissible range (P) for the secondary screw was <3.5 mm, then a hybrid construct was utilized (3.5/3.0 mm). In cases where P was <3 mm, then both screws were studied at 3 mm (3.0/3.0 mm). Screw diameters that optimized trajectory and bony purchase, while remaining within the permissible range, were analyzed, tabulated, and recorded. On CT, along the trajectory of the screws, the image was cut and measured in terms of screw length, the narrowest portion of the lamina, vertical angle, and horizontal angle in both primary and secondary screws. On the individually separated cervical spine segments in cadavers (11 of 18), we performed caliper measurements on the same portions that were measured on CT. It could not be exactly the same portions, however, due to the 3-dimensional characteristics of the specimens. RESULTS: For C3, only 1 specimen allowed 2 screws (3/3 mm), while the remaining specimens permitted a unilateral primary screw (3.5 or 3 mm) only. For C4, 37% of specimens allowed 2 screws (3.5/3 mm or 3/3 mm), but the rest allowed only a unilateral primary screw (3.5 or 3 mm). For C5, 58% allowed 2 screws (3.5/3.5, 3.5/3, or 3/3 mm). For C6, 89% of specimen allowed 2 screws (3.5/3.5, 3.5/3, or 3/3 mm). For C7, all levels allowed 2 screws (3.5/3.5, 3.5/3, 4/4, 4/3, 4.5/3, 4.5/3.5, or 4/3.5 mm). On CT, the average lengths of the 1- and 2-degree screws were 26.14 and 24.01 mm, respectively. The average vertical and horizontal angles were 22.26 and 40.66 degrees for the 1-degree screw, and 3.45 and 45.59 degrees for the 2-degree screw. On cadavers, the average lengths of the 1- and the 2-degree screws were 22.58 and 23.44 mm, respectively. The average vertical and horizontal angles were 23.67 and 54.44 degrees for the 1-degree screw, and 2.28 and 54.89 degrees for the 2-degree screw. CONCLUSIONS: This is a report of the anatomy of the lamina in the subaxial cervical spine with the special reference to translaminar screws. It was analyzed with CT and cadaveric spines along with simulated screw trajectories. For the 1-degree translaminar screw, the entry point is the distance of the diameter of desired screw superior to the inferior margin of lamina-spinous process junction. The trajectory should be targeted toward the most superomedial corner of lateral mass. For the 2-degree translaminar screw, the entry point is the distance of the diameter of desired screw below the superior margin of lamina-spinous process junction, and the target is the most superolateral corner of lateral mass, which is typically horizontal. Further studies are needed to assess the feasibility of translaminar screw insertion in the actual subaxial cervical spine.

Two-Year Outcomes from a Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion vs. Non-Surgical Management for Sacroiliac Joint Dysfunction.

BACKGROUND: Sacroiliac joint (SIJ) dysfunction is an important and underappreciated cause of chronic low back pain. OBJECTIVE: To prospectively and concurrently compare outcomes after surgical and non-surgical treatment for chronic SIJ dysfunction. METHODS: One hundred and forty-eight subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (SIJF, n = 102) or non-surgical management (NSM, n = 46). SIJ pain (measured with a 100-point visual analog scale, VAS), disability (measured with Oswestry Disability Index, ODI) and quality of life scores were collected at baseline and at scheduled visits to 24 months. Crossover from non-surgical to surgical care was allowed after the 6-month study visit was complete. Improvements in continuous measures were compared using repeated measures analysis of variance. The proportions of subjects with clinical improvement (SIJ pain improvement ≥20 points, ODI ≥15 points) and substantial clinical benefit (SIJ pain improvement ≥25 points or SIJ pain rating ≤35, ODI ≥18.8 points) were compared. RESULTS: In the SIJF group, mean SIJ pain improved rapidly and was sustained (mean improvement of 55.4 points) at month 24. The 6-month mean change in the NSM group (12.2 points) was substantially smaller than that in the SIJF group (by 38.3 points, p<.0001 for superiority). By month 24, 83.1% and 82.0% received either clinical improvement or substantial clinical benefit in VAS SIJ pain score. Similarly, 68.2% and 65.9% had received clinical improvement or substantial clinical benefit in ODI score at month 24. In the NSM group, these proportions were <10% with non-surgical treatment only. Parallel changes were seen for EQ-5D and SF-36, with larger changes in the surgery group at 6 months compared to NSM. The rate of adverse events related to SIJF was low and only 3 subjects assigned to SIJF underwent revision surgery within the 24-month follow-up period. CONCLUSIONS: In this Level 1 multicenter prospective randomized controlled trial, minimally invasive SIJF with triangular titanium implants provided larger improvements in pain, disability and quality of life compared to NSM. Improvements after SIJF persisted to 24 months. This study was approved by a local or central IRB before any subjects were enrolled. All patients provided study-specific informed consent prior to participation.

Comparison of Intraoperative C-Arm Fluoroscopy to Postoperative Radiographs in Operative Fracture Fixation.

The purpose of this study is to evaluate the differences between intraoperative C-arm images and postoperative plain film radiographs and the utility of each in assessing fracture fixation and determining postoperative management. Intraoperative and postoperative images with varying fracture types and locations were analyzed. C-arm images were compared to postoperative plain film radiographs for each treated fracture and reviewed by two orthopaedic surgeons. Image adequacy and quality for each radiograph were analyzed. The quality of reduction and fixation was also analyzed. Information was apparent on the postoperative radiographs, such that a reviewer felt that the postoperative treatment plan should change in 8.2% of cases. In the cases where treatment change was recommended, fracture gap, rotation, and angulation were found to be the strongest predictors. The ability of intraoperative and postoperative images to reflect fracture gap, rotation, and angulation may vary between images.

Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes.

BACKGROUND: Sacroiliac joint (SIJ) dysfunction is a prevalent cause of chronic, unremitting lower back pain. OBJECTIVE: To concurrently compare outcomes after surgical and nonsurgical treatment for chronic SIJ dysfunction. METHODS: A total of 148 subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (n = 102) or nonsurgical management (n = 46). Pain, disability, and quality-of-life scores were collected at baseline and at 1, 3, 6, and 12 months. Success rates were compared using Bayesian methods. Crossover from nonsurgical to surgical care was allowed after the 6-month study visit was complete. RESULTS: Six-month success rates were higher in the surgical group (81.4% vs 26.1%; posterior probability of superiority > 0.9999). Clinically important (≥ 15 point) Oswestry Disability Index improvement at 6 months occurred in 73.3% of the SIJ fusion group vs 13.6% of the nonsurgical management group (P < .001). At 12 months, improvements in SIJ pain and Oswestry Disability Index were sustained in the surgical group. Subjects who crossed over had improvements in pain, disability, and quality of life similar to those in the original surgical group. Adverse events were slightly more common in the surgical group (1.3 vs 1.1 events per subject; P = .31). CONCLUSION: This Level 1 study showed that minimally invasive SIJ fusion using triangular titanium implants was more effective than nonsurgical management at 1 year in relieving pain, improving function, and improving quality of life in patients with SIJ dysfunction caused by degenerative sacroiliitis or SIJ disruptions. Pain, disability, and quality of life also improved after crossover from nonsurgical to surgical treatment.

The insertion technique of translaminar screws in the thoracic spine: computed tomography and cadaveric validation.

BACKGROUND CONTEXT: Translaminar screws can be a good salvage technique in some cases of severe deformities, infection, tumor, osteoporosis, and revision cases with altered anatomy. To our knowledge, the insertion technique for translaminar screws in the thoracic spine has not been studied. PURPOSE: To suggest a safe insertion technique of translaminar screws in the thoracic spine. STUDY DESIGN: A cadaveric study. METHODS: Fifteen cadaveric spines were harvested from T1 to T12, and 1-mm computed tomography (CT) scans and three-dimensional reconstructions were obtained to rule out any bony anomaly. Eleven of the cadaveric spines were separated at each level from T1 to T12 (Group S) and four were not separated (Group N-S). Translaminar screws were inserted into every level along the trajectories proposed by the previous studies. The screw diameter was determined based on the reference article. For T1-T6, the screw diameter selected was 4 mm, and for T7-T12, a 3.5-mm diameter screw was used instead. The entry point for the 1° screw was at a distance equal to the diameter of the desired screw above the inferior margin of the spinolaminar junction. To create the trajectory, a drill guide was inserted at the entry point and directed toward the middle portion of the base of the transverse process of the contralateral side and was followed carefully to not break the inner/outer cortex of the lamina. The length of the drilled hole, representing the trajectory of the screw made by the drill guide, was measured, and the 1° screws were inserted according to the length measured. The entry point for the 2° screw was at a distance equal to the diameter of the screw below the superior margin of the base of the spinous process and lamina junction. The drill guide was pointed toward the inferior angle of the contralateral junction of the rib and the vertebra along the slope of the contralateral lamina. The 2° screw was inserted in the same manner as previously described. The 2° screw diameter was downsized if there was not enough space because of the 1° screw. For each vertebra from the 11 separated cadaveric spines, inner or outer cortex breakage was checked visually. For the remaining four nonseparated spines, CT scans were used to find any inner or outer cortex breakage. RESULTS: Thirty-three vertebral levels were abandoned from Group S because of altered anatomy (eg, fusion, fracture during separation, anatomical anomaly of having only 11 thoracic spine segments). Out of 147 vertebral levels, there was no vertebra that did not allow screw insertion. No specimen required using smaller diameter 2° screw because of blockage of the 1° screw. There was no cortical breakage by the screws in Group S. In Group N-S, CT scan showed four inner cortex breakages and three outer cortex breakages, all of which were slight cortical breakages. There were no facet injuries due to the screws in Group N-S. There was no blockage of the ribs during screw placement in all specimens, and the drill guide could lean against the rib for guidance because the angle of the rib and the opposite lamina tended to be the same. CONCLUSIONS: Translaminar screws can be inserted relatively safely in the thoracic spine. For the 1° translaminar screw, the entry point is at a distance equal to the diameter of the desired screw superior to the inferior margin of the lamina-spinous process junction. The trajectory should be targeted toward the center of the base of the contralateral transverse process. For the 2° translaminar screw, the entry point is at a distance equal to the diameter of the desired screw below the superior margin of lamina-spinous process junction, and the target is the inferior angle of the junction of the rib and vertebra on the contralateral side.

Outcome of percutaneous sacroiliac joint fixation with porous plasma-coated triangular titanium implants: an independent review.

DESIGN: Independent retrospective review of a single surgeon's experience with a new technique of SI fixation. OBJECTIVE: Examine results of percutaneous fixation of the SI joint with porous coated triangular titanium implants. BACKGROUND: Diagnosis and treatment of a dysfunctional sacroiliac joint is challenging as well as controversial. Recently, percutaneous stabilization techniques have been implemented for fixation. There is minimal literature published on this technique. METHODS: Charts, radiographs, and CT scans of 31 patients operated on by a single surgeon were de-identified and randomized and then reviewed by investigators not involved with the care of the patients. Reviewers had no relationship with the implant manufacturer at the time of the review. OUTCOME MEASURES: intraoperative and postoperative complication, EBL, hospital stays, postoperative image location and number of lucent implants, ingrowth into implants, and bone across SI joint. RESULTS: 27 patients expressed satisfaction, 4 patients did not. Pain relief was noted to be Complete (16 patients), Excellent (5 patients), Good (9 patients), and Fair (1 patients). Four patients had postoperative complications. These were infected hematoma (2), L5 nerve root irritation (1), and L5-S1 discitis (1). One patient required revision. On 6 month postop CT scan, 18/19 patients had radiographic evidence of bone ingrowth and bone into or across the SI joint was evident in 8/19 patients. Lucency was noted around at least one implant in 5/19 patients. CONCLUSIONS: Results are promising for the use of this novel implant for a carefully selected group of patients with disabling SI dysfunction.

The utility of routine postoperative radiographs after cervical spine fusion.

BACKGROUND CONTEXT: The senior author (JAG) recently published an article questioning the utility of routine postoperative radiographs after lumbar spine fusion. That study concluded that routine postoperative radiographs in the presence of a normal physical examination rarely change the clinician's management of these patients. Our aim was to repeat this protocol in patients after cervical spine fusion. We hypothesized that routine postoperative radiographs are unnecessary in most cases after cervical spine fusion. PURPOSE: The purpose of this study was to determine the usefulness of routine postoperative cervical spine radiographs after cervical spine fusion as to whether they help to guide clinical decision making within the first postoperative year. STUDY DESIGN: This is a retrospective chart review of 383 patients who underwent a cervical spine fusion over a 5-year period. Seven different surgeons performed the cervical spine fusions. Our review assessed a total of 1,155 postoperative clinic visits. METHODS: Each clinical postoperative visit was reviewed. The history and exam were graded as either normal or abnormal, and any plain radiographs obtained were graded similarly as either normal or abnormal. Each patient's notes were followed up to 1 year postoperatively. Each patient had to have at least two postoperative visits with X-rays to be included in the study. We then noted any further action taken by the clinician based on the appearance of the radiograph in conjunction with the history and exam. RESULTS: In patients with normal history and exam presentations, further action was taken only 5/879 (0.57%) of the time, sometimes even in the presence of abnormal radiographs. The actions included two surgical revisions, two prolongations of cervical collar immobilization, and one patient who underwent a flexion/extension radiographic evaluation and subsequent prolonged cervical collar immobilization. There were 276 visits with abnormal history and exam; of these, 34/276 (12.3%) had abnormal X-rays. Of the clinic visits with abnormal history and exam and abnormal X-rays, 15/34 (44%) went on to revision. CONCLUSIONS: Routine postoperative radiographs after cervical spine fusion rarely appear to be of value when patients present with a normal history and exam and may expose patients to unnecessary diagnostic studies and expenses. Patients exhibiting a normal postoperative history and exam are likely to have no further additional action taken in the presence of either normal or abnormal radiographs.

Biomechanical comparison of a novel C1 posterior locking plate with the harms technique in a C1-C2 fixation model.

STUDY DESIGN: A biomechanical testing protocol was used to study atlantoaxial fixation techniques in a human cadaveric model. OBJECTIVE: To compare the in vitro biomechanics of locking plate fixation of the posterior arch of C1 to C2 laminar screw fixation, with that of conventional C1 lateral mass to C2 pars screw fixation. SUMMARY OF BACKGROUND DATA: Current methods of atlantoaxial fixation pose a risk to neurologic and vascular structures. A novel posterior locking plate for C1 was designed, that when rigidly linked to C2 translaminar screws may offer alternative C1-C2 fixation with greatly decreased surgical risk. No comparative in vitro biomechanical testing has been previously done to evaluate the feasibility of this method. METHODS: Cadaveric and CT assessments of the thickness of the C1 ring were performed. Seven spines (C0-C4) were evaluated in flexion-extension, left-right bending, and left-right axial rotation in a cadaveric C1-C2 fixation model. Three conditions were evaluated: (1) intact spine, and after odontoidectomy, (2) C1 plate to C2 laminar screw fixation, (3) C1 lateral mass to C2 pars screw fixation. Flexibility and motion data were compared using a 1-way RM analysis of variance and Student-Newman-Kuels tests. RESULTS: Anatomic data indicated that 6 mm of screw purchase was viable for C1 plate fixation. Both the Harms and C1-plated conditions significantly reduced global flexibility in flexion-extension and left-right axial rotation. Motion at the C1-C2 level was significantly reduced for all loading modes for both instrumented conditions with the exception of the C1 plate in right bending. No significant differences occurred between the 2 fixation methods. CONCLUSION: A novel C1 posterior locking plate was designed and tested in a C1-C2 fixation model. The C1 locking plate technique functioned in an equivalent manner to the existing Harms technique. The C1 plate may be a viable alternative that is technically less demanding with decreased surgical risk.

Use of spectral vegetation indices derived from airborne hyperspectral imagery for detection of European corn borer infestation in Iowa corn plots.

Eleven spectral vegetation indices that emphasize foliar plant pigments were calculated using airborne hyperspectral imagery and evaluated in 2004 and 2005 for their ability to detect experimental plots of corn manually inoculated with Ostrinia nubilalis (Hübner) neonate larvae. Manual inoculations were timed to simulate infestation of corn, Zea mays L., by first and second flights of adult O. nubilalis. The ability of spectral vegetation indices to detect O. nubilalis-inoculated plots improved as the growing season progressed, with multiple spectral vegetation indices able to identify infested plots in late August and early September. Our findings also indicate that for detecting O. nubilalis-related plant stress in corn, spectral vegetation indices targeting carotenoid and anthocyanin pigments are not as effective as those targeting chlorophyll. Analysis of image data suggests that feeding and stem boring by O. nubilalis larvae may increase the rate of plant senescence causing detectable differences in plant biomass and vigor when compared with control plots. Further, we identified an approximate time frame of 5-6 wk postinoculation, when spectral differences of manually inoculated "second" generation O. nubilalis plots seem to peak.

Progressive cervical kyphosis associated with botulinum toxin injection.

Weakness of the neck extensors can lead to "dropped head syndrome", a condition of progressive cervical kyphosis in which a patient is unable to hold their head up against the force of gravity. This condition can be associated with structural abnormalities of the spine as found in ankylosing spondylitis and vertebral fractures. Neuromuscular disorders, such as myasthenia gravis, muscular dystrophies, inflammatory myopathies, and motor neuron disorders such as amyotrophic lateral sclerosis (ALS) have also been reported as etiologies of dropped head syndrome. In this article, we describe an elderly woman with rapidly progressive cervical kyphosis following an injection of botulinum toxin A into her neck extensor musculature.

Cryptococcal osteomyelitis in a 20-year-old male with sarcoidosis.

BACKGROUND CONTEXT: We present the case of a 20-year-old male with sarcoidosis with cryptococcal infection of the spine. PURPOSE: To present the case and add to the existing body of literature on clinical cryptococcal infection. STUDY DESIGN/SETTING: An academic tertiary care center. METHODS: Chart review and clinical examination.

Weather conditions and spinal patients.

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the effects of various weather conditions on reported health status. SUMMARY OF BACKGROUND DATA: Existing literature shows no definite conclusions regarding the effect of weather on patients with spinal pathology. METHODS: Initial visit data from 23 American centers participating in the National Spine Network included demographic information and SF-36-based health status. Weather conditions when and where patients were seen were obtained from the National Climatic Data Center and U.S. Naval Observatory. SF-36 outcomes were predicted using multiple regression techniques from weather parameters, which included high and low temperature, average dew point, wet bulb, barometric pressure, total precipitation, phase of the moon, and length of sunlight. RESULTS: A total of 26,862 of 54,062 patients were identified. Two models were compared: model 1 included the above weather predictors and model 2 added age and gender. For each SF-36 scale and subscale and the Physical and Mental composite Scores, both models were statistically significant, although only model 2 for physical function produced an R value greater than 1%. Barometric pressure was the only weather predictor that was consistently significant. Increased pressure was associated with worse outcomes. Although age and gender were significant additions to the prediction equation, overall, the practical contribution was minimal. CONCLUSION: A statistically significant relationship between weather factors and SF-36-based health status exists but has minimal clinical significance. These factors had minimal if any effect on mental health-related scores bringing into question either the relationship between weather and psychological status, at least in patients with spinal problems or the usefulness of the instrument used.

Lumbar arthrodesis for degenerative conditions.

There is significant disagreement among spine surgeons regarding the optimal technique of arthrodesis for treatment of degenerative disorders of the lumbar spine. Degenerative conditions of the lumbar spine include degenerative disk "disease," post-decompression degeneration, degenerative spondylolisthesis, junctional degeneration, spondylolis, and low-grade lytic spondylolisthesis. Although it is impossible to develop strict evidence-based criteria for the selection of one surgical approach over another, some generalizations are possible based on empiric process, anecdotal experience, and published surgical series. Patient selection, cessation of nicotine use, and use of autologous bone graft are factors that influence clinical outcome after lumbar arthrodesis.

Sustainability of insect resistance management strategies for transgenic Bt corn.

Increasing interest in the responsible management of technology in the industrial and agricultural sectors of the economy has been met thorough the development of broadly applicable tools to assess the "sustainability" of new technologies. An arena ripe for application of such analysis is the deployment of transgenic crops. The new transgenic pesticidal or plant-incorporated protectant (PIP) crops have seen widespread application in the United States based on the features of higher yield, lower applications of insecticides, and control of mycotoxin content. However, open rejection of these new crops in Europe and in other countries has been a surprising message and has limited their worldwide acceptance. The US Environmental Protection Agency's (USEPA) Office of Pesticide Programs (OPP) has worked on the development and analysis of insect resistance management (IRM) strategies and has mandated specific IRM requirements for Bacillus thuringiensis (Bt) crops since 1995 under the Food, Fungicide, Insecticide, and Rodenticide Act. Improvement of data quality and sustainability of IRM strategies have been targeted in an ongoing partnership between the USEPA Office of Research and Development and the Office of Pesticide Programs that will further enhance the agency's ability to develop sustainable insect resistance management strategies for transgenic field corn (Bt corn) producing B. thuringiensis (Bt) insecticidal proteins.

Complete arcuate foramen precluding C1 lateral mass screw fixation in a patient with rheumatoid arthritis: case report.

Case report of a complete arcuate foramen in a human atlas vertebra inhibiting the placement of lateral mass screw instrumentation at C1. Our objective is to report the presentation of the case, the operative considerations, and the management for this anatomic variation. The groove for the vertebral artery on the posterolateral surface of the atlas (C1) varies in size and depth from a slight impression to a clear sulcus. With anomalous ossification the sulcus can be bridged which results in a posterolateral tunnel within the posterior arch of the atlas. With increasing rates of screw fixation instrumentation that include the atlas, it is of paramount importance to know the location and course of the vertebral artery in relation to the planned route of instrumentation. The patient underwent a posterolateral fusion from C1 to C4 using autogenous iliac crest bone graft. Internal fixation from C2 to C4 was obtained using lateral mass screw instrumentation. After the vertebral artery was identified passing through the posterior arch of C1, sublaminar wires were utilized for fixation from C1 to C2. The patient responded well to surgical intervention without complications. Abnormal vertebral artery coursing through a posterolateral tunnel in the posterior arch of C1 has been described and its incidence has a range from 1.14% to 18%. When this variant is present, lateral mass screw fixation at C1 may be contra-indicated. We recommend close scrutiny of preoperative radiographs to avoid the possibility of endangering the vertebral artery when this situation exists.