Rare presentation of intradural calcium pyrophosphate dihydrate crystal deposition.

Calcium pyrophosphate dihydrate crystal deposition (CPPD), also known as pseudogout, can have spinal manifestations in roughly one quarter of patients. We present a rare, intradural manifestation of CPPD requiring surgical intervention, with a review of pertinent differential diagnoses on imaging. A 48-year-old male presented with urinary retention, and was found to have an intradural lesion with peripheral enhancement on gadolinium T1-weighted magnetic resonance imaging. Due to the patient's progressive neurological deterioration, he was taken for a minimally invasive approach for resection of the lesion. Histopathological analysis revealed crystal deposits with rhomboidal birefringence consistent with CPPD. The imaging features of this lesion were atypical for any of the traditional intradural extramedullary lesions. Typically seen extradurally, recognizing CPPD as a potential culprit for intradural compression is helpful to recognize for providers.

High lead impedances requiring revision during vagal nerve stimulator generator replacement.

OBJECTIVE: Vagal nerve stimulation (VNS) therapy is among the growing options in the treatment of intractable epilepsy. The phenomenon of surprise lead impedance issues found at the time of surgery resulting in unplanned lead revision is a challenge with this type of device. We reviewed our experience with VNS revisions. MATERIAL AND METHODS: We retrospectively reviewed the records of all adult and pediatric patients between January 2009 and September 2018 who underwent surgery for VNS therapy, including revision surgery. Office and operative notes were reviewed to obtain the indications and operative details for VNS placement. RESULTS: A total of 570 operations were reviewed. The indication was intractable epilepsy in all cases. Primary implantation was performed in 232 patients, while the remaining 338 cases were revision cases of various natures. Surprise high lead impedance was found in 10 (3%) of these cases, resulting in a significantly increased complexity of surgery in those instances. CONCLUSION: Lead impedance issues can be caused by disconnection, electrode fracture, hardware failure, or tissue scarring but ultimately require a more extended surgery than may be initially planned. Anticipating the potential for a more extensive operation than a simple generator replacement may prevent perioperative frustrations on both sides.

A comparison of minimally invasive posterior cervical decompression and open anterior cervical decompression and instrumented fusion in the surgical management of degenerative cervical myelopathy.

OBJECTIVE Minimally invasive posterior cervical decompression (miPCD) has been described in several case series with promising preliminary results. The object of the current study was to compare the clinical outcomes between patients undergoing miPCD with anterior cervical discectomy and instrumented fusion (ACDFi). METHODS A retrospective study of 74 patients undergoing surgery (45 using miPCD and 29 using ACDFi) for myelopathy was performed. Outcomes were categorized into short-term, intermediate, and long-term follow-up, corresponding to averages of 1.7, 7.7, and 30.9 months, respectively. Mean scores for the Neck Disability Index (NDI), neck visual analog scale (VAS) score, SF-12 Physical Component Summary (PCS), and SF-12 Mental Component Summary (MCS) were compared for each follow-up period. The percentage of patients meeting substantial clinical benefit (SCB) was also compared for each outcome measure. RESULTS Baseline patient characteristics were well-matched, with the exception that patients undergoing miPCD were older (mean age 57.6 ± 10.0 years [miPCD] vs 51.1 ± 9.2 years [ACDFi]; p = 0.006) and underwent surgery at more levels (mean 2.8 ± 0.9 levels [miPCD] vs 1.5 ± 0.7 levels [ACDFi]; p < 0.0001) while the ACDFi patients reported higher preoperative neck VAS scores (mean 3.8 ± 3.0 [miPCD] vs 5.4 ± 2.6 [ACDFi]; p = 0.047). The mean PCS, NDI, neck VAS, and MCS scores were not significantly different with the exception of the MCS score at the short-term follow-up period (mean 46.8 ± 10.6 [miPCD] vs 41.3 ± 10.7 [ACDFi]; p = 0.033). The percentage of patients reporting SCB based on thresholds derived for PCS, NDI, neck VAS, and MCS scores were not significantly different, with the exception of the PCS score at the intermediate follow-up period (52% [miPCD] vs 80% [ACDFi]; p = 0.011). CONCLUSIONS The current report suggests that the optimal surgical strategy in patients requiring dorsal surgery may be enhanced by the adoption of a minimally invasive surgical approach that appears to result in similar clinical outcomes when compared with a well-accepted strategy of ventral decompression and instrumented fusion. The current results suggest that future comparative effectiveness studies are warranted as the miPCD technique avoids instrumented fusion.

Minimally invasive approach for the treatment of intradural spinal pathology.

OBJECT: A wide variety of spinal intradural pathology traditionally has been treated from a midline posterior laminectomy using standard microsurgical techniques. This approach has been successful in treating the pathology; however, it carries a risk of postoperative complications including CSF leakage, wound infection, and spinal instability. The authors describe a minimally invasive surgical (MIS) approach to treating spinal intradural pathology with a low rate of postoperative complications. METHODS: Through a retrospective review of a prospectively collected surgical database, the authors identified 26 patients who underwent 27 surgeries via an MIS approach for intradural pathology of the spine. Using a tubular retractor system and an operative microscope, the authors were able to treat all patients with a unilateral, paramedian, and muscle-splitting technique. They then collected data regarding operative blood loss, length of stay, imaging characteristics, and outcomes. RESULTS: Eight cervical, 8 thoracic, and 11 lumbar intradural pathological entities, which included 14 oncological lesions, 4 Chiari I malformations, 4 arachnoid cysts, 3 tethered cords, 1 syrinx, and 1 chronic visceral pain, were treated via an MIS approach. The average blood loss was 197 ml and the average hospital stay was 3 days. One patient had to return to the operating room for noninfectious wound dehiscence. One patient required reoperation 18 months after the initial surgery for recurrence of the initial pathology. There was no CSF leak, no infection, and no spinal instability associated with the initial surgery on follow-up. CONCLUSIONS: Intradural spinal pathology can be safely and effectively treated with MIS approaches without an increased risk of neurological injury. This approach may also offer a reduced postoperative length of stay, risk of CSF leak, and risk of future spinal instability.

Does One Week of Postoperative Antibiotic Prophylaxis Reduce the Rate of Infection After Vagus Nerve Stimulator Surgery?

OBJECTIVE: Vagus nerve stimulation (VNS) therapy is an increasingly popular treatment for medically intractable epilepsy. During a review of our cases, we noted that one of the senior authors give patients 1 week of antibiotic prophylaxis after VNS surgery while the other does not. We reviewed our experience with postoperative antibiotic prophylaxis after VNS surgery. METHODS: We retrospectively reviewed the records of patients from January 2009 to September 2018 who had undergone surgery for VNS therapy, including generator replacement. The office and operative notes were reviewed to obtain the indications and operative details for VNS placement. RESULTS: A total of 570 operations were reviewed, 232 of which were primary implantations and 338 were revisions. The indication was intractable epilepsy in all cases. A total of 5 infections occurred, 4 in the group with postoperative antibiotic prophylaxis and 1 in the group without. The difference was not statistically significant. CONCLUSION: Just as with any hardware implantation, infection of the hardware can lead to significant morbidity. However, the use of postoperative oral antibiotic prophylaxis did not show benefit in reducing the infection rate.

The History of Neurosurgical Spinal Oncology: From Inception to Modern-Day Practices.

The neurosurgical management of spinal neoplasms has undergone immense development in parallel with advancements made in general spine surgery. Laminectomies were performed as the first surgical procedures used to treat spinal neoplasms. Since then, neurosurgical spinal oncology has started to incorporate techniques that have developed from recent advances in minimally invasive spine surgery. Neurosurgery has also integrated radiotherapy into the treatment of spine tumors. In this historical vignette, we present a vast timeline spanning from the Byzantine period to the current day and recount the major advancements in the management of spinal neoplasms.

Selection of Neurological Surgery Applicants and the Value of Standardized Letters of Evaluation: A Survey of United States Program Directors.

BACKGROUND: The letter of recommendation (LOR) represents a nonstandardized way to evaluate residency candidates. The goal of this project was to assess the current components of the Electronic Residency Application Service application and to determine and develop support for a standardized letter of evaluation (SLOE) in the resident selection process. METHODS: A 16-question survey was sent to US neurosurgery program directors. In addition to demographic information, respondents were asked to rank 7 aspects of the current application (1-7), evaluate the inclusion of specific standardized questions about applicants (yes or no), note their agreement with statements about LORs (on a 5-point Likert scale), and provide any additional comments. RESULTS: Fifty-three of 113 program directors (47%) completed the survey. The interview (average rank, 2.0 ± 1.4), United States Medical Licensing Exam step 1 score (2.86 ± 1.4), and LOR (2.96 ± 1.5) were ranked as the most important aspects of the application. Agreement was high for items regarding the utility of the current LOR (51%-78% agreement). Almost two-thirds (65%) of program directors agreed that implementing a standardized LOR would improve the resident selection process. Inclusion of questions regarding applicants' work ethic, teamwork, communication, professionalism, and initiative were strongly supported (>80% in favor), whereas including a question on theoretical rank position was mixed (54%). CONCLUSIONS: Most neurosurgical program directors agree that increasing the objectivity of the application would be beneficial, including the addition of standardized questions. However, there is only moderate interest in implementing an SLOE.

The effect of minimally invasive dorsal cervical decompression for myelopathy on spinal alignment and range of motion.

OBJECTIVE: Minimally invasive dorsal cervical decompression (miDCD) has been reported as a novel alternative to open dorsal decompression techniques such as laminectomy, laminoplasty, or laminectomy and fusion. Only limited data have been presented regarding the effects of a minimally invasive approach on cervical motion and alignment. The object of the current study is to provide a more comprehensive analysis of radiographic outcomes following miDCD. PATIENTS AND METHODS: Thirty-five patients who had undergone miDCD for myelopathy were included. Exclusion criteria included prior cervical spine surgery, prior cervical spine fracture, fusion of the cervical spine during miDCD, and/or acute spinal cord injury. Analysis of x-rays included the following data elements: degrees of flexion, degrees of extension, and total range of motion; C2-C7 angle as a measure of cervical lordosis; C2-C7 sagittal vertical axis; effective lordosis; and C7 slope. Patient reported outcome measures included neck Visual Analog Score (VAS), Neck Disability Index (NDI), SF-12 Physical Component Score (PCS), SF-12 Mental Component Score (MCS), Nurick score, and modified Japanese Orthopedic Association Myelopathy scale (mJOA). RESULTS: Pre-operative to post-operative comparisons of all radiographic parameters - including total range of motion, C2-C7 Cobb angle, C2-C7 sagittal vertical axis, effective lordosis, and C7 slope angle - remained stable. Several clinical outcomes demonstrated statistical improvement, namely neck VAS, Nurick score, mJOA, NDI, and SF-12 PCS. CONCLUSIONS: miDCD can maintain cervical range of motion and alignment better than traditional laminectomy or laminoplasty techniques.

A comparison of hinge craniotomy and decompressive craniectomy for the treatment of malignant intracranial hypertension: early clinical and radiographic analysis.

OBJECT: Hinge craniotomy (HC) has recently been described as an alternative to decompressive craniectomy (DC). Although HC may obviate the need for cranial reconstruction, an analysis comparing HC to DC has not yet been published. METHODS: A retrospective review was conducted of 50 patients who underwent cranial decompression (20 with HC, 30 with DC). Baseline demographics, neurological examination results, and underlying pathology were reviewed. Clinical outcome was assessed by length of ventilatory support, length of intensive care unit stay, and survival at discharge. Control of intracranial hypertension was assessed by average daily intracranial pressure (ICP) for the duration of ICP monitoring and an ICP therapeutic intensity index. Radiographic outcomes were assessed by comparing preoperative and postoperative CT scans for: 1) Rotterdam score; 2) postoperative volume of cerebral expansion; 3) presence of uncal herniation; 4) intracerebral hemorrhage; and 5) extraaxial hematoma. Postoperative CT scans were analyzed for the size of the craniotomy/craniectomy and magnitude of extracranial herniation. RESULTS: No significant differences were identified in baseline demographics, neurological examination results, or Rotterdam score between the HC and DC groups. Both HC and DC resulted in adequate control of ICP, as reflected in the average ICP for each group of patients (HC = 12.0 +/- 5.6 mm Hg, DC = 12.7 +/- 4.4 mm Hg; p > 0.05) at the same average therapeutic intensity index (HC = 1.2 +/- 0.3, DC = 1.2 +/- 0.4; p > 0.05). The need for reoperation (3 [15%] of 20 patients in the HC group, 3 [10%] of 30 patients in the DC group; p > 0.05), hospital survival (15 [75%] of 20 in the HC group, 21 [70%] of 30 in the DC group; p > 0.05), and mean duration of both mechanical ventilation (9.0 +/- 7.2 days in the HC group, 11.7 +/- 12.0 days in the DC group; p > 0.05) and intensive care unit stay (11.6 +/- 7.7 days in the HC group, 15.6 +/- 15.3 days in the DC group; p > 0.05) were similar. The difference in operative time for the two procedures was not statistically significant (130.4 +/- 71.9 minutes in the HC group, 124.9 +/- 63.3 minutes in the DC group; p > 0.05). The size of the cranial defect was comparable between the 2 groups. Postoperative imaging characteristics, including Rotterdam score, also did not differ significantly. Although a smaller volume of cerebral expansion was associated with HC (77.5 +/- 54.1 ml) than DC (105.1 +/- 65.1 ml), this difference was not statistically significant. CONCLUSIONS: Hinge craniotomy appears to be at least as good as DC in providing postoperative ICP control and results in equivalent early clinical outcomes.

Complications of cranioplasty following decompressive craniectomy: analysis of 62 cases.

OBJECT: Decompressive craniectomy is a potentially life-saving procedure used in the treatment of medically refractory intracranial hypertension, most commonly in the setting of trauma or cerebral infarction. Once performed, surviving patients are obligated to undergo a second procedure for cranial reconstruction. The complications following cranial reconstruction are not well described in the literature and may very well be underreported. A review of the complications would suggest measures to improve the care of these patients. METHODS: A retrospective chart review was undertaken of all patients who had undergone cranioplasty during a 7-year period. Demographic data, indications for craniectomy, as well as preoperative, intraoperative, and postoperative parameters following cranioplasty, were recorded. Perioperative and postoperative complications were also recorded. Patients were classified as having no complications, any complications, and complications requiring reoperation. The groups were compared to identify risk factors predictive of poor outcomes. RESULTS: The authors identified 62 patients who had undergone cranioplasty. The immediate postoperative complication rate was 34%. Of these, 46 patients did not require reoperation and 16 did. Of those requiring reoperation, 7 were due to infection, 2 from wound breakdown, 2 from intracranial hemorrhage, 3 from bone resorption, and 1 from a sunken cranioplasty, and 1 patient's cranioplasty procedure was prematurely ended due to intraoperative hypotension and bradycardia. The only factor statistically associated with need for reoperation was the presence of a bifrontal cranial defect (bifrontal: 8 [67%] of 12, requiring reoperation; unilateral: 8 [16%] of 49 requiring reoperation; p < 0.01) CONCLUSIONS: Cranioplasty following decompressive craniectomy is associated with a high complication rate. Patients undergoing a bifrontal craniectomy are at significantly increased risk for postcranioplasty complications, including the need for reoperation.

The effect of length of follow-up on substantial clinical benefit thresholds in patients undergoing surgery for cervical degenerative myelopathy.

Patient-reported outcome measures are increasingly used to access pain, disability, physical function, and mental status to quantify effectiveness of surgical intervention in cervical myelopathy, yet each score has little meaning without established thresholds linked to clinical benefit. We set out to develop thresholds for substantial clinical benefit (SCB) in patients undergoing surgery for cervical myelopathy and to evaluate the effect of length of follow-up on SCB thresholds. Thirty-five patients undergoing spinal surgery for progressive cervical myelopathy were tracked from 2005 to 2015. Observations were categorized into three groups: short-term, intermediate, and long-term, corresponding to average follow-up intervals of 3.8, 9.2, and 29.0 months. SCB thresholds were calculated for neck visual analog score (VAS), Neck Disability Index (NDI), Short Form-12 physical (PCS), SF-12 mental component scores (MCS), and modified Japanese Orthopedic Association score (mJOA) using receiver operating curve analysis with a 5-level patient satisfaction index as the anchor. SCB thresholds for each outcome measure were obtained with a range of areas under the curve indicating varying degrees of discriminatory ability, reported with increasing length of follow-up. NDI and PCS were most discriminatory of SCB at any time period. Stratification of thresholds by length of time revealed a significant effect of follow-up time with NDI but not PCS. NDI and PCS thresholds have significantly strong discriminatory value in identifying patients receiving substantial clinical benefit with regard to cervical myelopathy. When NDI is used to predict outcome, choosing thresholds calibrated for follow-up time is recommended to maximize predictive power.

Beta blockers exposure and traumatic brain injury: a literature review.

Traumatic brain injury (TBI) continues to carry a significant public health burden and is anticipated to worsen worldwide over the next century. Recently the authors of several articles have suggested that exposure to beta blockers may improve mortality rates following TBI. The exact mechanism through which beta blockers mediate this effect is unknown. In this paper, the authors review the literature regarding the safety of beta blockers in patients with TBI. The findings of several recent retrospective cohort studies are examined and implications for future investigation are discussed. Future questions to be addressed include: the specific indications for the use of beta blockers in patients with TBI, the optimal type and dose of beta blocker given, the end point of beta blocker therapy, and the safety of beta blockers in cases of severe TBIs.

Perioperative results following lumbar discectomy: comparison of minimally invasive discectomy and standard microdiscectomy.

OBJECT: Minimally invasive lumbar discectomy is a refinement of the standard open microsurgical discectomy technique. Proponents of the minimally invasive technique suggest that it improves patient outcome, shortens hospital stay, and decreases hospital costs. Despite these claims there is little support in the literature to justify the adoption of minimally invasive discectomy over standard open microsurgical discectomy. In the present study, the authors address some of these issues by comparing the short-term outcomes in patients who underwent first time, single-level lumbar discectomy at L3-4, L4-5, or L5-S1 using either a minimally invasive percutaneous, muscle splitting approach or a standard, open, muscle-stripping microsurgical approach. METHODS: A retrospective chart review of 172 patients who had undergone a first-time, single-level lumbar discectomy at either L3-4, L4-5, or L5-S1 was performed. Perioperative results were assessed by comparing the following parameters between patients who had undergone minimally invasive discectomy and those who received standard open microsurgical discectomy: length of stay, operative time, estimated blood loss, rate of cerebrospinal fluid leak, post-anesthesia care unit narcotic use, need for a physical therapy consultation, and need for admission to the hospital. RESULTS: Forty-nine patients underwent minimally invasive discectomy, and 123 patients underwent open microsurgical discectomy. At baseline the groups did differ significantly with respect to age, but did not differ with respect to height, weight, sex, body mass index, level of radiculopathy, side of radiculopathy, insurance status, or type of preoperative analgesic use. No statistically significant differences were identified in operative time, rate of cerebrospinal fluid leak, or need for a physical therapy consultation. Statistically significant differences were identified in length of stay, estimated blood loss, postanesthesia care unit narcotic use, and need for admission to the hospital. CONCLUSIONS: In this retrospective study, patients who underwent minimally invasive discectomy were found to have similar perioperative results as those who underwent open microsurgical discectomy. The differences, although statistically significant, are of modest clinical significance.

Cargo areas of pickup trucks: an avoidable mechanism for neurological injuries in children.

OBJECT: Falls from pickup truck cargo areas represent a unique mode of injury in children and adolescents. The goal of this study was to identify the neurological spectrum of injuries resulting from children riding in the back of pickup trucks. METHODS: The authors undertook a retrospective review of the University of New Mexico Hospital trauma registry of data compiled over a 7-year period. Their goal was to identify instances in which a fall or ejection from a pickup truck cargo area was the mechanism of injury. The charts of pediatric patients (< or = 16 years of age) with neurological injuries were reviewed and analyzed. Seventy-three pediatric patients with injuries related to riding in the cargo areas of trucks were identified, of which 53 children (73%) had sustained neurological injuries. Among these 53 children, 64% sustained isolated head injuries, 15% isolated spine injuries, 9.4% combined spine and head injuries, 2% combined peripheral nerve, spine, and head injuries, 4% isolated peripheral nerve injuries, and 5.6% concussive events. In 53.4% of patients with neurological injuries the results of computed tomography (CT) examination were abnormal. In 36% of patients with Glasgow Coma Scale (GCS) scores of 14 to 15 there was evidence of intracranial hemorrhage on head CT scans. Injury Severity Scores were similar in the patients who were ejected and those who fell from cargo areas, but patients who were ejected had a lower mean GCS score than those who suffered falls (GCS score 12.5 and 14.3, respectively). CONCLUSIONS: Falls or ejections from pickup truck cargo areas result in a relatively high incidence of traumatic head, spine, and peripheral nerve injury. Head CT scanning should therefore be considered in pediatric patients with this mechanism of injury. Cargo area occupancy poses an unacceptable risk of injury and should be avoided.

Minimally Invasive Surgical Management of Thoracic Ossification of the Ligamentum Flavum Associated with X-linked Hypophosphatemia.

BACKGROUND: X-linked hypophosphatemia (XLH) is the most common inherited form of renal phosphate wasting and inherited rickets. Patients have hyperplasia of fibrochondrocytes in tendons and ligaments, causing the structures to thicken and calcify. Thickening of the lamina, hypertrophy of facet joints, and calcification of spinal ligaments are sequelae of this condition and can result in central or foraminal stenosis that compresses nerve roots or the spinal cord. We present a case of XLH with calcification of the ligamentum flavum in which the patient was operated on using minimally invasive posterior decompression. CASE DESCRIPTION: A 49-year-old man with a history of XLH presented to our emergency department with symptomatic myelopathy from multilevel thoracic stenosis. Radiographically, the calcified ligamentum flavum appeared to be the cause of the stenosis at various levels. The patient underwent a posterior decompression at the levels of compression, T4-T5, T8-T9, T9-T10, and T11-T12, via a minimally invasive spine surgery approach. Intraoperatively, the ligamentum flavum appeared to be both calcified and the source of spinal compression. Postoperatively, the patient experienced neurologic and radiographic improvement. CONCLUSION: Patients with a history of XLH and multilevel symptomatic spine stenosis can be treated successfully and safely with a minimally invasive posterior decompression.

Follow-up of stented carotid arteries by Doppler ultrasound.

OBJECTIVE: Blood flow velocity (BFV) in the carotid artery is altered by stent placement. The significance of these alterations is unknown. In our experience, both standard BFV criteria for stenosis and customized criteria recommended by other authors have led to high rates of false-positive studies. We reviewed our experience with Doppler ultrasonography immediately after extracranial carotid artery stent placement to define criteria for restenosis by BFV. METHODS: Complete carotid angiograms and BFV results were available for 114 patients treated between January 1998 and December 1999. Angiographic images obtained immediately after stent placement and at follow-up were measured for residual or recurrent stenosis by a blinded reviewer according to the North American Symptomatic Carotid Endarterectomy Trial method. Results of BFV studies obtained within 1 week of stent placement were interpreted by using two standard criteria (A, peak in-stent systolic velocity greater than 125 cm/s; B, internal carotid artery-to-common carotid artery ratio greater than 3.0) and two customized criteria (C, peak in-stent velocity greater than 170 cm/s; D, internal carotid artery-to-common carotid artery ratio greater than 2.0). The results of follow-up angiography and the most recent Doppler study were compared for nine patients. RESULTS: On the basis of an examination of Doppler studies obtained immediately after stent placement, 36 patients met Criterion A for stenosis according to measured BFV (corresponding mean angiographic stenosis, 14.73 +/- 18.45%), 3 patients met Criterion B (mean stenosis, 1.67 +/- 2.89%), 8 patients met Criterion C (mean stenosis, 12.61 +/- 13.18%), and 14 met Criterion D (mean stenosis, 7.98 +/- 21.74%). No patient with Doppler criteria for significant stenosis had more than 50% residual stenosis. Three of nine patients who underwent follow-up angiography had stenosis of 50% or more; of these three patients, two underwent second angioplasty procedures. The peak in-stent systolic velocity or internal carotid artery-to-common carotid artery BFV ratio for each of the three patients with restenosis, but not for the six other patients, had increased by more than 80% since the immediate post-stenting Doppler study. CONCLUSION: Strict BFV criteria for restenosis after carotid artery stenting are less reliable than change in BFV over time. An immediate post-stenting Doppler study must be obtained to serve as a reference value for future follow-up evaluation.

Treatment of a chronic Scedosporium apiospermum vertebral osteomyelitis. Case report.

Scedosporium apiospermum is a rare cause of fungal vertebral osteomyelitis that may result in chronic infection requiring multiple surgical interventions and long-term medical therapy. This case is the seventh one reported in the literature and is the first to include salvage surgery of a previous major spinal reconstruction. This report is also the first to describe the use of the new antifungal agent voriconazole. In treating this case of chronic vertebral osteomyelitis, several principles are emphasized from both the surgical and medical perspectives. From a surgical perspective, the use of salvage surgery, temporary avoidance of spinal instrumentation, and an appropriate choice of graft materials are emphasized. From a medical perspective, confirmation of the diagnosis, the need for long-term antifungal therapy, the need for long-term patient compliance, and the use of the new antifungal agent voriconazole are emphasized. Application of these principles has led to an adequate 2-year outcome.

In vitro biomechanics of cervical disc arthroplasty with the ProDisc-C total disc implant.

An in vitro biomechanical study was conducted to compare the effects of disc arthroplasty and anterior cervical fusion on cervical spine biomechanics in a multilevel human cadaveric model. Three spine conditions were studied: harvested, single-level cervical disc arthroplasty, and single-level fusion. A programmable testing apparatus was used that replicated physiological flexion/extension, lateral bending, and axial rotation. Measurements included vertebral motion, applied load, and bending moments. Relative rotations at the superior, treated, and inferior motion segment units (MSUs) were normalized with respect to the overall rotation of those three MSUs and compared using a one-way analysis of variance with Student-Newman-Keuls test (p < 0.05). Simulated fusion decreased motion across the treated site relative to the harvested and disc arthroplasty conditions. The reduced motion at the treated site was compensated at the adjacent segments by an increase in motion. For all modes of testing, use of an artificial disc prosthesis did not alter the motion patterns at either the instrumented level or adjacent segments compared with the harvested condition, except in extension.