Frank Eismont

Delivering charged antibiotics to the intervertebral disc is challenging because of the avascular, negatively charged extracellular matrix (ECM) of the tissue. The purpose of this study was to measure the apparent diffusion coefficient of two clinically relevant, charged antibiotics, vancomycin (positively charged) and oxacillin (negatively charged) in IVD. A one-dimensional steady state diffusion experiment was employed to measure the apparent diffusion coefficient of the two antibiotics in bovine coccygeal annulus fibrosus (AF) tissue. The averaged apparent diffusion coefficient for vancomycin under 20% compressive strain was 7.94 ± 2.00 × 10 m/s (n = 10), while that of oxacillin was 2.26 ± 0.68 × 10 m/s (n = 10). A student's t-test showed that the diffusivity of vancomycin was significantly lower than that of oxacillin. This finding may be attributed to two factors: solute size and possible binding effects. Vancomycin is approximately 3 times larger in molecular weight than o...

Little quantitative information exists on the kinetics of charged antibiotic penetration into human intervertebral discs (IVD). This information is crucial for determining the dosage to use, timing of administration, and duration of treatment for infected IVDs. The objective of this study was to quantitatively analyze the transport of various charged antibiotics into human lumbar IVDs. Penetration of charged and uncharged antibiotics into a human lumbar disc was analyzed using a 3D finite element model. The valence (z) of the electrical charge of antibiotics varied from z=+2 (positively charged) to z=-2 (negatively charged). An uncharged antibiotic (z=0) was used as a control. Cases with intravenous (IV) administrations of different charged antibiotics were simulated. Our results showed that the electrical charge had great effects on kinetics of an antibiotic penetration into the IVD; with higher concentrations and uptakes for positively charged antibiotics than those for negatively...

Chordoma is a rare, slow-growing malignant tumor arising from notochordal remnants. A retrospective review of patient records at two major referral centers was undertaken to assess the incidence, location, and prognostic factors of metastatic disease from chordoma. 219 patients with chordoma (1962-2009) were identified. 39 patients (17.8%) developed metastatic disease, most frequently to lung (>50%). Median survival from the time of initial diagnosis was 130.4 months for patients who developed metastatic disease and 159.3 months for those who did not (P = 0.05). Metastatic disease was most common in the youngest patients (P = 0.07), and it was 2.5 times more frequent among patients with local recurrence (26.3%) than in those without (10.8%) (P = 0.003). Patient survival with metastatic disease was highly variable, and it was dependent on both the location of the tumor primary and the site of metastasis. Metastasis to distal bone was the most rapid to develop and had the worst pro...

The efficacy of expansile cervical laminoplasty for cervical spondylotic myelopathy has been validated in the literature. To date, however, the majority of large, long-term data in the literature have originated in Japan. Few studies have originated from North America that include follow up greater than one year, and none of these includes a single surgeon's experience. This paper presents the retrospective results of a single surgeon with an average follow up of 47 months in a large population of North American patients. A single surgeon's series of 80 consecutive patients who underwent expansile open-door laminoplasty for cervical myelopathy was reviewed. The severity of disability was graded using the Nurick Functional Disability Score and the Miami Upper Extremity Function (MUEF) score. Patients were evaluated preoperatively, six months postoperatively, and at a minimum of 24 months postoperatively. All examinations were performed by a single physician. MRI scans of the cervical spine were obtained at four months postoperatively in all patients. Radiographs were used to evaluate postoperative lordosis. Average length of follow up was 47 months. Nurick scores improved from an average of 2.3 preoperatively to postoperative scores of 1.5 (p>.05) at six months and 1.4 (p>.05) at two years. MUEF scores also improved at both the six month and two year intervals. All patients had improved canal diameter on post-operative MRI scan evaluation obtained four months post-operatively. This study confirms that laminoplasty is a safe and effective treatment of cervical spondylotic myelopathy in the North American population. Case Series Level IV.

DESCRIPTION Lumbar spinal stenosis (LSS): a disease of epidemic proportions in the Nation is often treated by surgeries to decompress the spinal nerve. However, often after surgery, stenosis can propagate to adjacent spinal segments. We hypothesize that surgeries for LSS may change the biomechanical environment of the adjacent segments, eventually leading to adjacent segment disease (ASD). Accordingly, our objective is to investigate the biomechanical alterations of operated and adjacent spine levels (L3-L4 and L4-L5) occurring after performing these procedures. A finite elements model of the lumbar spine was constructed from CT scan of a healthy male subject and validated by using FEBio 1.8.0 (M-S Research Lab., Univ. Utah). A hybrid loading protocol was applied on examining the model

An examination of the medical and physiological effects of functional electrical stimulation (FES) applied to the quadriceps muscle of five paraplegic male volunteers with complete spinal cord injuries was performed. FES training was provided three days a week over a 12-week period using a progressive resistive exercise protocol. Stimulation was applied through use of a closed-loop microprocessor-based FES system. Prior to the start of and immediately following the 12-week training period, subjects were assessed on several measures, including quadriceps muscle bulk and histochemistry, laboratory studies, echocardiography, and arm ergometry exercise. Results of the study indicated substantial increases in muscle strength and muscle bulk. At the outset of the study one patient suffered a patellar fracture. No significant changes in pretraining and posttraining general examinations, laboratory studies, echocardiography, or arm ergometry exercise testing were noted.

A retrospective study was used to review fellowship applications over 3 years. To assess the prevalence of research misrepresentation in orthopedic fellowship applications, and to compare such activity between subspecialties (e.g., spine, sports, hand). Competition for orthopedic surgery fellowships is intense. The applicant pool includes orthopedic, plastic, and general surgeons, as well as neurosurgeons. Residency and fellowship training programs in other disciplines have documented shocking levels of misrepresentation in the curriculum vitae of prospective applicants. However, no study has looked at orthopedic residents applying for subspecialty fellowship programs. A retrospective analysis investigated 280 applications for fellowship positions in the department of orthopedic surgery at the authors' academic institution from 1996 to 1998 inclusively. To allow for press and publication delays, a minimum 24-month follow-up period was instituted. The listings of applicants' ...

Numerous reports in the literature describe cerebrospinal fluid (CSF) leaks resulting from dural tears; however, most of these reports document symptoms of incidental durotomy occurring ,48 hours postoperatively. This case report describes patients with symptoms of CSF leak occurring a few days to a few weeks after lumbar spine surgery who required additional surgery to repair the dura and alleviate their symptoms. Records for patients who had lumbar spine surgery performed by 2 spine surgeons at a single institution between 1990 and 2005 were reviewed. After additional surgery to repair what appeared to be late postoperative durotomies, 2 patients recovered fully from their orthostatic headaches and reported satisfactory relief of their preoperative neurological symptoms. They did not have symptoms of spinal fluid leakage following surgery, and no intraoperative dural tear was noted, suggesting these cases may have been secondary to late postoperative durotomy. The incidence of durotomy has been noted to be increased in patients undergoing revision spine surgery secondary to adhesions and scarring of the dura. As this was the first spine operation for both cases reported, we believe that residual bone spikes are responsible for puncturing the dural sac postoperatively. Spine surgeons should be exceedingly cautious in inspecting for bone spikes following an extensive dural exposure and recognize the significance of the new onset of an orthostatic headache, even days or weeks following spine surgery.

Four patients with traumatic occipitoatlantal dislocation are presented. The dislocations were the result of rapid deceleration motor vehicle accidents. The mechanism of injury was by hyperextension-rotation combined with a distraction force. Three patients sustained multiple injuries. Neurologic findings were variable. One patient with complete cord transection and closed head trauma died 4 days after the injury. In the three surviving patients, the occipitoatlantal dislocation was not diagnosed by the initial examiner. Prompt recognition and stabilization are essential to avoid further neurologic injury. Care must be taken not to increase the dislocation. A halo applied before operation facilitates reduction and allows posterior occipitoatlantal fusion to be performed under optimum conditions.

A randomized clinical trial of 15 patients with acute spinal cord injuries was performed to test the hypothesis that rotating treatment tables prevent deep venous thrombosis in this population. Four of 5 control (nonrotated) patients developed distal and proximal thrombi, assessed by 125I fibrinogen leg scans and impedance plethysmography. In comparison, only 1 of 10 treated (rotated) patients developed both distal and proximal thrombosis (P = 0.007). These results suggest but do not prove that rotating treatment tables prevent the development of proximal deep venous thrombosis in spinal cord-injured patients. Larger clinical trials are needed to confirm this heretofore undocumented benefit of rotating treatment tables.