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STUDY DESIGN: Compare the effectiveness of two different techniques for the management of osteoid osteoma of the spine. OBJECTIVE: To describe the technique, feasibility, and indications of two different minimally invasive surgical methods for the treatment of osteoid osteoma of the spine. SUMMARY OF THE BACKGROUND DATA: Current treatment of osteoid osteoma of the spine is usually conventional surgical excision. The successful treatment of osteoid osteoma of the appendicular skeleton by percutaneous radiofrequency probe ablation is known; however, there have been only a few cases reported utilizing this method to treat osteoid osteoma of the spine. The high success rate of percutaneous transpedicle vertebral biopsy and diskectomy led us to believe this technique can also be applicable for the treatment of osteoid osteoma of the spine. METHODS: Two patients with symptomatic osteoid osteoma of the spine underwent two different surgical managements with local anesthesia. In one patient, the osteoid osteoma was localized in the apex of the right L4 superior articular process joint. Under computed tomography guidance he underwent radiofrequency coagulation with the use of a radiofrequency generator at 90 degrees for 240 seconds. The lesion in the second patient was located in the right pedicle of the T9 vertebra close to the exiting nerve root and was cored out by means of a special percutaneous instrument designed for percutaneous biopsy under fluoroscopic guidance. RESULTS: Both patients experienced immediate relief of pain, resumed their regular activities, and also remained free of symptoms after the 2.5- and 3-year follow-up. CONCLUSION: Minimally invasive surgery can successfully be applied in the treatment of osteoid osteoma of the lumbar spine. When the nidus is not adjacent to the neural elements radiofrequency thermal ablation can be an effective and safe treatment of osteoid osteoma in the spine. [ABSTRACT FROM AUTHOR]

Introduction: A variety of biodegradable implants (screws, rods, plates and cages) are available which are composed of many different biodegradable polymers with varying characteristics. The present review of animal and clinical studies examines the efficacy and safety of biodegradable implants in spinal fracture intervention., Methods: A review of the literature through March 2018 was performed using PubMed and Cochrane databases. Success rates were calculated according to sufficient tissue biocompatibility, solid clinical fusion and propensity for osseointegration., Results: 49 articles (24 animal and 25 human studies) were included. In animal experiments, the overall success rate for spinal fusion was 60.3%, while the mean success rate regarding the cervical spine was 51.8% compared to 68.1% for the lumbar spine (p = 0.002). In studies involving control group(s): the mean bioabsorbable implant success rate for spinal fusion was 42% compared to 57% for conventional implants (p = 0.0016). In the lumbar spine pL-lactide acid (PLLA) had 75.2% success rate compared to poly (L-lactide-co-DL-lactide) (PLDLLA) at 53.4% (p = 0.003). In clinical studies, the overall mean success rate was 89%, while the mean success rate regarding the cervical spine was 92%, as compared to 83.6% for the lumbar spine (p = 0.001). In studies involving control group(s): the mean bioabsorbable implant success rate was 75% compared to a conventional implant mean success rate of 97% (p<0.0001). In the cervical spine PLLA had a 98.7% success rate compared to 90% with PLDLLA (p = 0.015). In the lumbar spine PLDLLA had 84.7% success rate compared to 63.6% for poly-glycolic acid (PGA) (p = 0.085)., Discussion: Studies combined biodegradable and conventional implants. Polymers were used in various combinations and surface modification of the implants also varied. Comparison studies were of small sample size. Animal and clinical studies diverged. The current data are not encouraging. The end-point of assessing osseointegration varies in the studies and is indeterminate. In early stages the structure comparison of osseous restoration using biodegradable implants appears inferior to utilization of conventional cages and instrumentation. There is no statistically significant evidence supporting the efficacy of biodegradable implants replacing traditional instrumentation. There is a lack of prospective clinical trials with long-term follow-up regarding utilization of biodegradable implants and the available data does not support their routine use in spinal fracture intervention., (Copyright © 2018. Published by Elsevier Ltd.)

Introduction: This paper describes surgical options for Osteoporotic vertebral compression fracture (OVCF) with acute flexible or chronic rigid kyphosis, and pseudarthrosis complicated with pain and neurologic deficit., Methods: This study has two components. a) A prospective clinical study of surgical treatment of 31 patients (age: 69±11 years) with either acute flexible or progressive pseudarthrotic kyphosis manifested with severe pain or neurological deficit between 2010 and 2014. Eleven patients exhibited neurocompression (Frankel B, C, D). Surgery consisted in indirect reduction, kyphoplasty, and short posterior instrumentation in 28 patients and multilevel instrumentation in three. b) The second component involved a literature search of OVCF complicated with acute or painful chronic deformities and neurologic deficit, managed with open surgical approach., Results: Indirect reduction, kyphoplasty and short posterior stabilization can restore satisfactory anatomic alignment and neurological deficit. Multilevel instrumentation was used for rigid long kyphosis. Complications were related to a) screw pull out and junctional kyphosis (4 patients) one of the patients also developed anterior migration of cement, b) cement leakage (4 patients). L5 radiculopathy occurred in one patient. The others remained asymptomatic. The literature review concluded that corpectomy with anterior, posterior or combined instrumentations is indicated for burst fractures, or rigid kyphosis with neurocompression. Prompt decompression with anatomical alignment may restore paraplegia. Complications were germane to osteoporotic bone predisposing to hardware loosening or cut out and dislodgement of instrumentation., Discussion: Neurologic deficit associated with fractures or progressive pseudarthrotic kyphosis effectively may respond to indirect postural reduction, kyphoplasty and posterior percutaneous short segment transpedicle instrumentation. For burst fractures and rigid chronic kyphosis corpectomy reconstructed with cages and anterior, or posterior or combined instrumentations can restore and maintain normal anatomy. The following guidelines for optimal surgical instrumentation have been established: To prevent screw loosening and junctional kyphosis the instrumentation should not end within the kyphotic segment. Screws for anterior instrumentation should penetrate the contralateral cortex. Multiple site of fixation or combined anterior and posterior instrumentations dissipate stresses at any one site. Augmentation of transpedicle screw fixation with cement is a sound technical principle. Cement should inserted in a doughy state with minimal pressure to prevent cement complications., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The purpose of this novel study was to investigate the feasibility of unilateral transpedicular balloon kyphoplasty particularly of the upper thoracic vertebrae using an 11- gauge balloon and cement inserter, and to study the morphological parameters of the thoracic spine pedicles. We used four fresh frozen cadaveric thoracic spines with intact rib cages and skin for kyphoplasty from T1 to T12 vertebrae under C-arm fluoroscopy. The most limiting width of the pedicles 2.46+/-0.32mm was in the middle levels (T5-T8). The absolute minimum height of the pedicles was at T1 (3.80-3.87mm). All regions of the vertebral body were effectively targeted for cement augmentation. The average cement load of all the vertebral bodies was 43,22%. Using the kyphoplasty technique in combination with the pre-bent 11mm memory-alloy cement inserter allowed targeting of the desired position of the vertebral body for effective vertebral body cement augmentation.

Educational Objectives: As a result of reading this article, physicians should be able to:1.Understand the importance of early diagnosis and treatment of spinal infection in an effort to avoid devastating and crippling complications such as paralysis, painful deformity, and death.2.Understand current perceptions in the ongoing debate of whether operative or conventional treatment should be preferred and in which cases.3.Understand the latest advances in the surgical treatment of spinal infection, their indications, and their effectiveness.4.Understand the change in the traditionally held belief that in the presence of infection, the use of metal implants or grafts is not indicated. Controversy exists regarding optimal treatment for pyogenic spinal infection. The authors systematically reviewed peer-reviewed published clinical trials in the English language through 2009 on the clinical presentation, complications, and conservative and operative treatments of pyogenic spinal infection. The cornerstone of therapy for uncomplicated spondylodiskitis is intravenous antibiotics followed by oral antibiotics and bracing. Surgery is effective in complicated cases and improves sagittal balance, restores neurological impairment, and relieves severe pain. In cases of delayed diagnosis or surgery, potential early devastating and late crippling complications may occur. To the authors' knowledge, no Level I studies compare operative vs conservative treatment of pyogenic spinal infection., (Copyright 2012, SLACK Incorporated.)

Study Design: Retrospective, consecutive patient series., Objective: To quantify the risks and the complications associated with screw fixation devices of the cervical spine., Summary of Background Data: The usefulness of lateral mass internal fixation has been well documented in the clinical setting. However, there is a paucity of studies examining the complications associated with these devices in a degenerative clinical setting., Methods: From 1999 to 2007, 225 consecutive patients underwent posterior cervical fixation using a screw-plate and polyaxial screw-rod implant systems. There were 105 women and 120 men (age range: 45 to 84 y; mean, 68 y). In all patients, the surgical indication was cervical spondylosis with myelopathy. Mean follow-up interval was 18 months (range: 12 to 72 mo). Screw position was evaluated by computed tomography scanning postoperatively in all patients. Clinical and radiographic outcome was assessed at each visit after surgery., Results: Intraoperative complications include fracture of lateral mass in 27 screws placement and nerve irritation in 3 bicortical screws. Early complications include hematoma formation in 2 cases and C5 root palsy in 5 cases after spinal canal decompression. Late complications include pseudarthrosis in 6 cases and screw pull-out in 3 cases. There were no cases of spinal cord or vertebral artery injury, infections, deaths, or adjacent segment disease. All patients had radiographic union, and no patient developed mechanical implant failure requiring removal of instrumentation. Reoperation was required in 14 (6.2%) cases because of nerve injury, hematoma formation, pseudarthrosis, and screw pull-out., Conclusions: Our clinical findings indicate that lateral mass fixation can be used safely with minimal complications and low rate of morbidity for cervical myelopathy treatment.

Background: The burden of musculoskeletal disorders (MSD) on the general health and well-being of the population has been documented in various studies. The objective of this study was to explore the association between MSD and the quality of life and mental health of patients and to discuss issues concerning care seeking patterns in rural Greece., Methods: Patients registered at one rural Primary Care Centre (PCC) in Crete were invited to complete the Nordic Musculoskeletal Questionnaire (NMQ) for the analysis of musculoskeletal symptoms, together with validated instruments for measuring health related quality of life (SF-36) and mental distress (GHQ-28)., Results: The prevalence rate of MSD was found to be 71.2%, with low back and knee pain being the most common symptoms. Most conditions significantly impaired the quality of life, especially the physical dimensions of SF-36. Depression was strongly correlated to most MSD (p < 0.001). Multiple logistic analyses revealed that patients who consulted the PCC due to MSD were likely to have more mental distress or impaired physical functioning compared to those who did not., Conclusion: Musculoskeletal disorders were common in patients attending the rural PCC of this study and were associated with a poor quality of life and mental distress that affected their consultation behaviour.

Percutaneous radiofrequency ablation is the treatment of choice for osteoid osteoma of the appendicular skeleton. However, difficulties in localizing the lesion in the spine and its proximity to neural elements have yet to make it the prevalent treatment for spine. This study assesses the safety and effectiveness of two percutaneous techniques for ablating osteoid osteoma of the spine. Seven patients were treated between 1998 and 2005. Four patients underwent percutaneous radiofrequency coagulation. The lesions were located at the articular processes of L3 and L4, the lamina of L3 and in the head of the 11th rib. Three patients with lesions in close proximity to neural structures (pedicle of T9, the posterolateral inferior aspect of L3 vertebral body and the inferior articular process of C5) were subjected to percutaneous core excision. Mean follow-up was 4.2 +/- 1.6 years. Three out of four patients who underwent radiofrequency ablation had an immediate and sustained response. One patient with a lesion in the head of the rib failed to respond. The three patients in the group of pecutaneous core excisional biopsy demonstrated immediate relief of pain. However, one patient experienced relapse of symptoms 6 months after transpedicular core excision. CT scan suggested partial targeting of the lesion that corroborated with histologic examination revealing only reactive tissue. Subsequent percutaneous core excision was successful. Therefore, the overall success rate was 85.7%. Mean VAS improved dramatically from 9 +/- 1 to 2 +/- 1 after surgery (P < 0.05). No neurological or other complications were encountered. This study indicates that radiofrequency ablation of spinal osteoid osteomas is safe and reasonably effective when an intact cortical shell separates the nidus from the neural elements. Percutaneous core excision can obviate the risk of thermal damage for lesions located in close proximity to the neural elements. Effectiveness of treatment can also be evaluated by CT scan and histological examination. Difficulties in targeting the nidus can lead to treatment failure. The minimal morbidity and the effectiveness of these minimally invasive procedures make them a valid alternative in the treatment of spinal osteoid osteoma.

This study investigated the effect of endplate deformity after an osteoporotic vertebral fracture in increasing the risk for adjacent vertebral fractures. Eight human lower thoracic or thoracolumbar specimens, each consisting of five vertebrae were used. To selectively fracture one of the endplates of the middle VB of each specimen a void was created under the target endplate and the specimen was flexed and compressed until failure. The fractured vertebra was subjected to spinal extension under 150 N preload that restored the anterior wall height and vertebral kyphosis, while the fractured endplate remained significantly depressed. The VB was filled with cement to stabilize the fracture, after complete evacuation of its trabecular content to ensure similar cement distribution under both the endplates. Specimens were tested in flexion-extension under 400 N preload while pressure in the discs and strain at the anterior wall of the adjacent vertebrae were recorded. Disc pressure in the intact specimens increased during flexion by 26 +/- 14%. After cementation, disc pressure increased during flexion by 15 +/- 11% in the discs with un-fractured endplates, while decreased by 19 +/- 26.7% in the discs with the fractured endplates. During flexion, the compressive strain at the anterior wall of the vertebra next to the fractured endplate increased by 94 +/- 23% compared to intact status (p < 0.05), while it did not significantly change at the vertebra next to the un-fractured endplate (18.2 +/- 7.1%, p > 0.05). Subsequent flexion with compression to failure resulted in adjacent fracture close to the fractured endplate in six specimens and in a non-adjacent fracture in one specimen, while one specimen had no adjacent fractures. Depression of the fractured endplate alters the pressure profile of the damaged disc resulting in increased compressive loading of the anterior wall of adjacent vertebra that predisposes it to wedge fracture. This data suggests that correction of endplate deformity may play a role in reducing the risk of adjacent fractures.

The pathophysiology of intervertebral disc degeneration has been extensively studied. Various factors have been suggested as influencing its aetiology, including mechanical factors, such as compressive loading, shear stress and vibration, as well as ageing, genetic, systemic and toxic factors, which can lead to degeneration of the disc through biochemical reactions. How are these factors linked? What is their individual importance? There is no clear evidence indicating whether ageing in the presence of repetitive injury or repetitive injury in the absence of ageing plays a greater role in the degenerative process. Mechanical factors can trigger biochemical reactions which, in turn, may promote the normal biological changes of ageing, which can also be accelerated by genetic factors. Degradation of the molecular structure of the disc during ageing renders it more susceptible to superimposed mechanical injuries. This review supports the theory that degeneration of the disc has a complex multifactorial aetiology. Which factors initiate the events in the degenerative cascade is a question that remains unanswered, but most evidence points to an age-related process influenced primarily by mechanical and genetic factors.

PubMed and Ovid Medline were searched to investigate the role of intramedullary nailing in the treatment of diaphyseal humeral non-union. Of 474 abstracts, 9 retrieved articles fulfilled our inclusion criteria and described management in 166 cases of humeral shaft non-union using several types of intramedullary nails. Union ranged from 40 to 100%; part of the variation could be explained by the quality index of the selected articles. Exchange nailing alone was not effective. Exposure of the fracture site and use of bone grafting were key to successful treatment. The total incidence of severe complications, including radial nerve damage, was very low. Thus, intramedullary nailing in the treatment of humeral shaft non-unions can lead to successful outcomes when associated with autologous bone grafting.

The authors report the case of a young patient in which, during removal of a Seidel nail four years after healing of a mid shaft fracture of the humerus, bone formation into the central canal of the nail through the peripheral slots, prevented the three spread distal fins of the nail to close. The nail could only be extracted by forceful use of the extracting instrument, fortunately without complication.

Background: Previous clinical studies have shown the safety and effectiveness of balloon kyphoplasty in the treatment of pathological vertebral compression fractures (VCFs). However, they have not dealt with the impact of relatively common comorbid conditions in this age group, such as spinal stenosis, and they have not explicitly addressed the use of imaging as a prognostic indicator for the restoration of vertebral body height. Neither have these studies dealt with management and technical problems related to surgery, nor the effectiveness of bone biopsy during the same surgical procedure. This is a prospective study comparing preoperative and postoperative vertebral body heights, kyphotic deformities, pain intensity (using visual analogue scale) and quality of life (Oswestry disability questionnaire) in patients with osteoporotic vertebral compression fractures (OVCFs) and osteolytic vertebral tumors treated with balloon kyphoplasty., Methods: Thirty-two consecutive patients, 27 OVCFs (49 vertebral bodies [VBs]) and 5 patients suffering from VB tumor (12 VBs) were treated by balloon kyphoplasty. The mean age was 68.2 years. All patients were assessed within the first week of surgery, and then followed up after one, three and six months; all patients (27 OVCFs and 5 tumor patients) were followed up for 12 months, 17 patients (14 OVCFs and 3 tumors) were followed up for 18 months and 9 patients (8 OVCFs and 1 tumor) were followed up for 24 months (mean follow up 18 months). The correction of kyphosis and vertebral heights were measured by comparing preoperative and postoperative radiographic measurements., Results: Thirty-one patients (96.9%) exhibited significant and immediate pain improvement: 90% responded within 24 h and 6.3% responded within 5 days. Daily activities improved by 53% on the Oswestry scale. In the OVCF group, kyphosis correction was achieved in 24/27 patients (89.6%) with a mean correction of 7.6 degrees . Anterior wall height was restored in 43/49 VBs (88%) (mean increment of 4.3 mm), and mid vertebral body height was restored in 45/49 VBs (92%) (mean increment of 4.8 mm). Edema (high intensity signal) on short tau inversion recovery (STIR) was evidenced in all OVCF patients who experienced symptoms for less than nine months and was associated with correction of deformity. Cement leakage was the only technical problem encountered; it occurred in 5/49 VBs (10.2%) of the osteoporotic group and 1/12 VBs (8.3%) of the tumor group but had no clinical consequences. The incidence of leakage to the anterior epidural space was 2%. Spinal stenosis was present in three patients (11.1%) who responded successfully to subsequent laminectomy. Retrieval of tissue samples for biopsy was successful in 10/15 cases (67%). New fractures occurred in the adjacent level in 2/27 OVCF patients (7.4%)., Conclusions: Associated spinal stenosis with OVCF should not be overlooked; STIR MRI is a good predictor of deformity correction with balloon kyphoplasty. The prevalence of a new OVCF in the adjacent level is low.

Background Context: In patients with osteoporosis, changes in spinal alignment after a vertebral compression fracture (VCF) are believed to increase the risk of fracture of the adjacent vertebrae. The alterations in spinal biomechanics as a result of osteoporotic VCF and the effects of deformity correction on the loads in the adjacent vertebral bodies are not fully understood., Purpose: To measure 1) the effect of thoracic VCFs on kyphosis (geometric alignment) and the shift of the physiologic compressive load path (loading alignment), 2) the effect of fracture reduction by balloon (bone tamp) inflation in restoring normal geometric and loading alignment and 3) the effect of spinal extension alone on fracture reduction and restoration of normal geometric and loading alignment., Study Design/setting: A biomechanical study using six fresh human thoracic specimens, each consisting of three adjacent vertebrae with all soft tissues and bony structures intact., Methods: In order to reliably create fracture, cancellous bone in the middle vertebral body was disrupted by inflation of bone tamps. After removal of the bone tamps, the specimen was compressed using bilateral loading cables until a fracture was observed with anterior vertebral body height loss of >/=25%. Fracture reduction was performed under a compressive preload of 250 N first under the application of extension moments, and then using inflatable bone tamps. The vertebral body heights, kyphotic deformity of the fractured vertebra and adjacent segments and location of compressive load (cable) path in the fractured and adjacent vertebral bodies were measured on video-fluoroscopic images., Results: The VCF caused anterior wall height loss of 37+/-15%, middle-height loss of 34+/-16%, segmental kyphosis increase of 14+/-7.0 degrees and vertebral kyphosis increase of 13+/-5.5 degrees (p<.05). The compressive load path shifted anteriorly by about 20% of anteroposterior end plate width in the fractured and adjacent vertebrae (p=.008). Bone tamp inflation restored the anterior wall height to 91+/-8.9%, middle-height to 91+/-14% and segmental kyphosis to within 5.6+/-5.9 degrees of prefracture values. The compressive load path returned posteriorly relative to the postfracture location in all three vertebrae (p=.004): the load path remained anterior to the prefracture location by about 9% to 11% of the anteroposterior end plate width. With application of extension moment (6.3+/-2.2 Nm) until segmental kyphosis and compressive load path were fully restored, anterior vertebral body heights were improved to 85+/-8.6% of prefracture values. However, the middle vertebral body height was not restored and vertebral kyphotic deformity remained significantly larger than the prefracture values (p<.05)., Conclusions: The anterior shift of the compressive load path in vertebral bodies adjacent to VCF can induce additional flexion moments on these vertebrae. This eccentric loading may contribute to the increased risk of new fractures in osteoporotic vertebrae adjacent to an uncorrected VCF deformity. Bone tamp inflation under a physiologic preload significantly reduced the VCF deformity (anterior and middle vertebral body heights, segmental and vertebral kyphosis) and returned the compressive load path posteriorly, approaching the prefracture alignment. Application of extension moments also was effective in restoring the prefracture geometric and loading alignment of adjacent segments, but the middle height of the fractured vertebra and vertebral kyphotic deformity were not restored with spinal extension alone.

The natural history of uncomplicated hematogenous pyogenic spondylodiscitis is self-limiting healing. However, a variable degree of bone destruction frequently occurs, predisposing the spine to painful kyphosis. Delayed treatment may result in serious neurologic complications. Early debridement of these infections by percutaneous transpedicular discectomy can accelerate the natural process of healing and prevent progression to bone destruction and epidural abscess. The purpose of this manuscript is to present our technique of percutaneous transpedicular discectomy (PTD), to revisit this minimally invasive surgical technique with stricter patient selection, and to exclude cases of extensive vertebral body destruction with kyphosis and neurocompression by epidural abscess, infected disc herniation, and foraminal stenosis. In a previously published report of 28 unselected patients with primary hematogenous pyogenic spondylodiscitis, the immediate relief of pain after PTD was 75%, and in the long-term follow-up, the success rate was 68%. Applying stricter patient selection criteria in a second series of six patients (five with primary hematogenous spondylodiscitis and one with secondary postlaminectomy-discectomy spondylodiscitis), all patients with primary hematogenous spondylodiskitis (5/5) experienced immediate relief of pain that remained sustained at 12-18 months follow-up. This procedure was not very effective, however, in the patient who suffered from postlaminectomy infection. This lack of response was attributed to postlaminectomy-discitis instability. The immediate success rate after surgery for unselected patients in this combined series of 34 patients was 76%. This technique can be impressively effective and the results sustained when applied in the early stages of uncomplicated spondylodiscitis and contraindicated in the presence of instability, kyphosis from bone destruction, and neurological deficit. The special point of this procedure is a minimally invasive technique with high diagnostic and therapeutic effectiveness.

The immediate and long-term outcomes of 70 consecutive patients who underwent subaxial lateral mass fixation between June 1996 and June 2001 were reviewed. Intraoperative fluoroscopy and somatosensory evoked potential (SEP) monitoring were used in all patients. Immediate postoperative computed tomography (CT) was performed to determine screw trajectory and placement. Follow-up ranged from 2 to 7 years. Postoperative CT showed 206 (58%) of 356 screws had unicorticate and 42% bicorticate purchase. Furthermore, 96 (27%) screws had suboptimal trajectory, but only 5 of these screws minimally penetrated the foramen transversarium without resultant vascular or neurological sequelae. A sudden unilateral intraoperative SEP amplitude decrease during screw placement in 2 patients resolved with screw removal and alteration of screw trajectory. The overall fusion success rate was 91.5% and screw pull-out developed in 2 patients. The recommended drilling technique and trajectory (15 degrees - 25 degrees rostral in the sagittal plane, 20 degrees - 30 degrees lateral in the axial plane), supplemented bone grafting, and intraoperative SEP monitoring are all associated with good screw placement, fusion, and neurological outcome and are recommended for all lateral mass fusion procedures.

Forty-two patients who underwent decompressive surgery for cervical spondylotic myelopathy were studied. The pre- and postoperative magnetic resonance imaging (MRI) findings and the Japanese Orthopedic Association score were analyzed to evaluate whether the different appearances of intramedullary high-signal intensity on T2-weighted MRI are related to the surgical prognosis. Magnetic resonance imaging signal intensities were classified as type 0 if no intramedullary high-signal intensity on T2-weighted images was noted, type 1 if high-signal intensity involved only one segment, and type 2 if high-signal intensity extended over two segments. Statistical analyses of the recovery ratio showed that type 0 and type 1 intramedullary high-signal intensity indicates better prognosis than type 2.

The results of hemiarthroplasty for shoulder fracture were evaluated in 26 patients, 20 women and 6 men with a mean age of 64.7 +/- 8.2 years. The follow-up period was 2 to 7 years. Cofield prostheses were used for the first 10 patients and subsequently 9 Global and 7 Aequalis prostheses were implanted, all cemented. The clinical outcome was assessed using the Constant-Murley scale. The mean score, at the last follow-up, was 70.4 +/- 16.4 (39-96). Mean forward elevation of the arm was 150 degrees (300-175 degrees), mean abduction was 145 degrees (30 degrees -170 degrees), and mean external rotation was 30 degrees (10 degrees-45 degrees). In most of the cases internal rotation corresponded with a position of the dorsum of the hand at the L3 vertebrae. The patients in our series achieved their optimal clinical result within the first 6 months after operation. Shoulder hemiarthroplasty is a worthwhile procedure, giving predictable results provided the patients have been carefully selected, the individual anatomy of the shoulder is restored and an aggressive rehabilitation program is implemented during the first six months after surgery.

Osteoporosis is the most common contributing factor of spinal fractures, which characteristically are not generally known to produce spinal cord compression symptoms. Recently, an increasing number of medical reports have implicated osteoporotic fractures as a cause of serious neurological deficit and painful disabling spinal deformities. This has been corroborated by the present authors as well. These complications are only amenable to surgical management, requiring instrumentation. Instrumenting an osteoporotic spine, although a challenging task, can be accomplished if certain guidelines for surgical techniques are respected. Neurological deficits respond equally well to an anterior or posterior decompression, provided this is coupled with multisegmental fixation of the construct. With the steady increase in the elderly population, it is anticipated that the spine surgeon will face serious complications of osteoporotic spines more frequently. With regard to surgery, however, excellent correction of deformities can be achieved, by combining anterior and posterior approaches. Paget's disease of bone (PD) is a non-hormonal osteometabolic disorder and the spine is the second most commonly affected site. About one-third of patients with spinal involvement exhibit symptoms of clinical stenosis. In only 12-24% of patients with PD of the spine is back pain attributed solely to PD, while in the majority of patients, back pain is either arthritic in nature or a combination of a pagetic process and coexisting arthritis. In this context, one must be certain before attributing low back pain to PD exclusively, and antipagetic medical treatment alone may be ineffective. Neural element dysfunction may be attributed to compressive myelopathy by pagetic bone overgrowth, pagetic intraspinal soft tissue overgrowth, ossification of epidural fat, platybasia, spontaneous bleeding, sarcomatous degeneration and vertebral fracture or subluxation. Neural dysfunction can also result from spinal ischemia when blood is diverted by the so-called "arterial steal syndrome". Because the effectiveness of pharmacologic treatment for pagetic spinal stenosis has been clearly demonstrated, surgical decompression should only be instituted after failure of antipagetic medical treatment. Surgery is indicated as a primary treatment when neural compression is secondary to pathologic fractures, dislocations, spontaneous epidural hematoma, syringomyelia, platybasia, or sarcomatous transformation. Five classes of drugs are available for the treatment of PD. Bisphosphonates are the most popular antipagetic drug and several forms have been investigated.

Seventy-one percutaneous transpedicle biopsy specimens were taken from 68 patients with cervical, thoracic, lumbar, or sacral vertebral lesions, with the patients under local anesthesia. Sixty-one procedures were done with fluoroscopic guidance and seven procedures were done with computed tomography guidance. Twenty-one patients were diagnosed as having infectious spondylodiscitis, three had tuberculosis, two had coccidiomycosis, two had brucellosis, one had blastomycosis, one had an echinococcus cyst, six had primary neoplasms, 14 had metastatic neoplasms, five had osseous repair for insufficiency fractures, seven had osteoporotic fractures, and one had Paget's disease of bone. In the four remaining patients, the biopsy initially was negative but it was proven to be false-negative because of faulty biopsy technique. The percutaneous transpedicle approach for biopsy is safe, efficacious, and cost-effective. False-negative results and complications can be avoided when adhering to the technical details of this procedure.

Sixteen patients, with a fracture of the upper humerus treated with hemiarthroplasty, were followed-up for 45.7 +/- 15.1 (20-72) months after surgery. The results were assessed using the Constant-Murley scale. The mean score was 75.8 +/- 15.7 (54-96) points out of a possible maximum of 100. At the time of their last follow-up they underwent CT of the fractured and contralateral humerus. Humeral length and retroversion were measured and evaluated. A very good final outcome (Constant score more than 71) was achieved in patients with a difference in retroversion less than 10 degrees and a difference in length less than 14 mm, between fractured and sound humerus. The mean difference in retroversion was 8.7 degrees and the mean difference in length was 0.65 cm, between fractured and sound humerus. We attribute the very good clinical outcome in our series to the quality of the anatomical reconstruction that was performed.

Study Design: A biomechanical study using human cadaveric cervical spines was conducted., Objective: To determine whether the cervical stability achieved with lateral mass fixation using unicortical screw purchase is comparable with that obtained with lateral mass fixation using bicortical screw purchase., Summary of Background Data: Cervical lateral mass fixation has traditionally required bicortical screw fixation, which is associated with potential injury to the vertebral vessels and cervical nerve roots. Unicortical fixation eliminates these possible complications. Limited stability studies suggest that unicortical fixation in the lateral masses provides stability comparable with that of bicortical fixation. However, no comprehensive biomechanical study has compared the cervical stability between bicortical and unicortical lateral mass fixations., Methods: A total of 11 human cadaveric cervical spinal sections between C3 and C5 were tested in flexion-extension, torsion, and lateral bending modes, both with and without laminectomy, on an MTS machine. The lateral masses were plated and tested with bicortical screws in all 11 specimens. Long (14 mm) unicortical screws were used in 8, and short (10 mm) screws were used in 6 of the 11 specimens. Displacement then was determined in millimeters (of flexion-extension and lateral bending) and degrees (of torsion) for each value of applied torque (0.45, 0.9, 1.35, 1.8 Nm). Two-way analysis of variance using unequal data sets then was applied., Results: Analysis demonstrates that bicortical constructs were, on the average, stiffer than unicortical constructs in most bending modes. No significant differences were found, however, between bicortical constructs and long unicortical constructs without laminectomy. In the presence of a destabilizing laminectomy, a difference was found in the lateral bending mode. More differences were found between bicortical and short unicortical constructs both with and without laminectomy., Conclusions: Cervical lateral mass fixation with "long" (up to but not through the anterior lateral mass cortex) unicortical Magerl screws may provide an acceptable and safe alternative to bicortical screw fixation.

Study Design: This report describes two cases of acute spondylodiscitis, caused by, complicating two different conditions: microdiscectomy for herniated nucleus pulposus and decompressing laminotomy for spinal stenosis., Objective: To describe a rare and life-threatening spinal infection and discuss its successful management., Summary of Background Data: To our knowledge, no published reports in the English language have described this potentially devastating infection as a complication of elective noninstrumented discectomy or decompressive laminotomy., Methods: Two cases of a very early onset of acute spondylodiscitis, caused by, after minimally invasive lumbar spine surgeries are presented. The elapsed time between these two complications was 1 week. The clinical presentation was characteristically stormy in both cases. On postoperative day 2, the patients developed high fever with intense chills and concomitant acute low back pain rapidly increasing in severity. The overall clinical appearance was alarming. The patients were carefully investigated immediately and scrutinized for possible origin of the infection. Treatment consisted of prompt intravenous antibiotics and surgical debridement., Results: The history and clinical manifestations of postoperative spondylodiscitis were corroborated with magnetic resonance imaging findings and bacteriologic and hematologic laboratory examination. Blood cultures revealed as the responsible pathogenic microorganism. The source of the pathogens was contaminated normal saline used for surgical lavage. Both patients were able to completely resume their previous occupations after aggressive surgical debridement/irrigation and 3 months of antibiotic treatment., Conclusions: may become a potential pathogen, causing severe spinal infection after elective surgery. For prompt diagnosis and effective treatment of this life-threatening infection, one should maintain high index of suspicion and should not procrastinate in initiating treatment, which should consist of appropriate intravenous antibiotics and surgical debridement.

In order to assess the effectiveness of calcium sulphate (plaster of Paris; POP) as a substitute for autologous bone graft, we performed lumbar intervertebral fusion in mature sheep using POP and a variety of other graft materials, and reviewed the literature. The osteoconductivity of the POP grafts was compared to that of grafts carried out with autogenous iliac crest, frozen allogeneic bone, and ProOsteon 500 coralline bone. We also compared the osteogenicity of POP to admixtures of autogenous iliac crest bone with POP and coralline bone, and to an osteoinductive demineralized sheep bone preparation (DBM). The substrates were loaded into tubular titanium mesh, implanted into excavated disc spaces and recovered after a period of 4 months. Fusion mass segments tested in flexion and tension showed that POP was equal to autogenous bone and most other substrates. The POP fusions were significantly tougher than the DBM fusions, even though histomorphometry failed to reveal differences in the amount of trabecular bone. We conclude that POP can be used to achieve a biomechanically stable interbody lumbar vertebral fusion. In addition, our literature review indicated that POP can be used as a vehicle for local delivery of antibiotics in bone infections.

A review of the literature was conducted to study the pathomechanics by which Paget's Disease of bone (PD) alters the spinal structures that result in distinct spinal pathologic entities such as pagetic spinal arthritis, spinal stenosis, and other pathologies, and to assess the best treatment options and available drugs. The spine is the second most commonly affected site with PD. About one-third of patients with spinal involvement exhibit symptoms of clinical stenosis. In only 12-24% of patients with PD of the spine is back pain attributed solely to PD, while in the majority of patients back pain is either arthritic in nature or a combination of a pagetic process and coexisting arthritis. Neural element dysfunction may be attributed to compressive myelopathy by pagetic bone overgrowth, pagetic intraspinal soft tissue overgrowth, ossification of epidural fat, platybasia, spontaneous bleeding, sarcomatous degeneration and vertebral fracture or subluxation. Neural dysfunction can also result from spinal ischemia, when blood is diverted by the so-called "arterial steal syndrome". Because the effectiveness of pharmacologic treatment for pagetic spinal stenosis has been clearly demonstrated, surgical decompression should only be instituted after failure of antipagetic medical treatment. Surgery is indicated as a primary treatment when neural compression is secondary to pathologic fractures, dislocations, spontaneous epidural hematoma, syringomyelia, platybasia, or sarcomatous transformation. Since, in the majority of cases with pagetic spinal involvement, there are also coexisting osteoarthritic changes, antipagetic medical treatment alone may be disappointing. Therefore, one must be careful before attributing low back pain to PD alone. Five classes of drugs are available for the treatment of PD: bisphosphonates, calcitonins, mithramycin (plicamycin), gallium nitrate, and ipriflavone. Bisphosphonates are the most popular, and several forms have been investigated, but only the following forms have been approved for clinical use: disodium etidronate, clodronate, aledronate, risedronate, neridronate, pamidronate, tiludronate, ibadronate, aminohydroxylbutylidene bisphosphonate, olpadronate, and zoledronate. Several of these forms are still under investigation.

Study Design: Retrospective., Objectives: To determine the incidence, clinical presentation, diagnostic laboratory values, imaging characteristics, and optimal treatment of hematogenous pyogenic facet joint infections., Summary of Background Data: There are 27 documented cases of hematogenous pyogenic facet joint infections. Data regarding incidence, clinical presentation, diagnosis, and treatment response are incomplete because of the paucity of reported cases., Methods: This is a retrospective study of all cases of hematogenous pyogenic facet joint infection treated at one institution. Data from previous publications were combined with the present series to identify pertinent clinical characteristics and response to treatment., Results: A total of six cases (4%) of hematogenous pyogenic facet joint infection were identified of 140 cases of hematogenous pyogenic spinal infection at our institution. Combining all reported cases reveals the following: The average patient age is 55 years. Ninety-seven percent of cases occur in the lumbar spine. Epidural abscess formation complicates 25% of the cases of which 38% develop severe neurologic deficit. Erythrocyte sedimentation rate and C-reactive protein are elevated in all cases. Staphylococcus aureus is the most common infecting organism. Magnetic resonance imaging is accurate in identifying the septic joint and associated abscess formation. Percutaneous drainage of the involved joint has a higher rate of success (85%) than treatment with antibiotics alone (71%), but the difference is not significant (P = 0.37)., Conclusions: Hematogenous pyogenic facet joint infection is a rare but underdiagnosed clinical entity. Facet joint infections may be complicated by abscess formation in the epidural space or in the paraspinal muscles. Uncomplicated cases treated with percutaneous drainage and antibiotics may fare better than those treated with antibiotics alone. Cases complicated by an epidural abscess and severe neurologic deficit should undergo immediate decompressive laminectomy.

Two cases of hematogenous, pyogenic, subaxial cervical facet joint infection are reported, and the literature is reviewed. Infection of the cervical facet joint is a rarely diagnosed condition; only one case has been reported in the literature. Lumbar facet joint infections are also rare but more commonly reported. Approximately one fourth of facet joint infections in the lumbar spine are complicated by epidural abscess formation, which can lead to a neurological deficit. Because of the paucity of reports on cervical facet joint infections, the clinical characteristics of this entity are not well known. Both patients presented with an acute onset of unilateral neck pain that radiated into the ipsilateral shoulder. Frank radicular pain was initially absent. Unilateral upper-extremity motor weakness that was attributed to associated epidural abscess or granulation tissue formation was also demonstrated in both patients. Leukocyte count and erythrocyte sedimentation rate were elevated in both cases. Magnetic resonance imaging was necessary to obtain an accurate diagnosis. Staphylococcus aureus was identified as the offending pathogen in both cases. Decompressive surgery and antibiotic therapy were required to cure the condition. One patient recovered completely and the other sustained a permanent motor deficit. Hematogenous cervical facet joint infection is a rare clinical entity that has many characteristics in common with the more-common lumbar homolog. All three reported cases, however, have been complicated by epidural abscess or granulation tissue formation that has led to a neurological deficit. This finding suggests that a facet joint infection in the cervical spine may have a less benign clinical course than that in the lumbar spine.

This review presents the history of chemonucleolysis, the techniques, indications, contraindications, and complications. Presenting an historical overview and comparison of success rates with surgical discectomy may provide a fresh understanding of the controversy surrounding chemonucleolysis and establish its efficacy in relation to more invasive treatments. A review of the literature from 1973 through 1998 for chemonucleolysis, open discectomy, and microdiscectomy provided published success rates for these procedures, and a mean rate with standard deviation was determined. In the experience and opinion of the authors, chemonucleolysis remains a viable alternative for patients who have exhausted all conservative means of treatment. Proper patient selection leads to success rates comparable to open discectomy and microdiscectomy.

We applied a new methodology in 7 patients with a fracture of the upper humeral head that required hemiarthroplasty, to implant a humeral prosthesis with an individualized posterior version. Our goal was to determine preoperatively the distance from the posterior edge of the bicipital groove where the lateral fin of the humeral prosthesis should sit, in order to reproduce the individual retroversion during surgery. Using three computed tomography scan sections of the upper humerus and image processing software, we estimated the above-mentioned distance in the sound humerus and implanted the prosthesis in each patient accordingly. The differences in retroversion between the left and right humeral heads permit a better approximation to normal applying this methodology than inserting the prosthesis in a standard retroversion.

We studied 35 successive patients who underwent subaxial lateral mass fixation between June 1994 and January 1996. Follow-up ranged from 2 to 3 1/2 years. Postoperative computed tomography scans showed 45 of 146 screws (31%) had suboptimal trajectory, but only 2 screws minimally impinged the foramen transversarium without adverse sequelae. The fusion rate was 89%. Study results show that optimal drilling technique and trajectory (15 degrees-25 degrees rostral in the sagittal plane, 20 degrees-30 degrees lateral in the axial plane) and intraoperative somatosensory evoked potential monitoring are associated with good screw placement and avoidance of complications, and bone grafting is associated with higher fusion rates.

Background: Intervertebral disk tissue is resistant to hematogenous infection because of its avascularity. However, spondylodiskitis is being diagnosed with increasing frequency because of advancement in magnetic resonance imaging technology. There is a dearth of information regarding the bacteriology, histomorphologic features, and radiopathologic correlation of spondylodiskitis., Design: The study population consisted of 20 patients diagnosed as having spondylodiskitis by magnetic resonance imaging with and without gadolinium 67 enhancement and bone scans with technetium Tc 99m or gallium citrate Ga 67. Twenty-seven biopsy and debridement specimens were obtained from these patients. The specimens were cultured for microorganisms and also processed for histopathologic testing. Tissue sections were examined with hematoxylin-eosin and stains for infectious agents (Gomori's methenamine-silver, Gram, and Ziehl-Neelsen stains)., Results: Where intervertebral disk tissue was present (23 of 27 cases), the morphologic changes included vascularization (with or without granulation tissue), myxoid degeneration, and necrosis. Chronic osteomyelitis was present in all 27 specimens and was associated with acute osteomyelitis in 7 cases (25%). Twenty-one of 27 cases had positive culture results (mostly pyogenic bacteria), but special stains revealed microorganisms in sections of the disk in only 4 cases (3 cases with gram-positive cocci and 1 with yeast consistent with Blastomyces). Florid acute inflammation was present in all the 4 cases., Conclusion: Histopathologic features of acute spondylodiskitis include vascular proliferation, myxoid degeneration, and necrosis of the disk tissue with adjacent chronic osteomyelitis. Acute inflammation is variable and when florid is usually associated with identifiable organisms on histologic examination. At biopsy, tissue should be submitted for culture, since culture has a high sensitivity and specificity for detecting the etiologic organism.

Study Design: In adult female sheep, histologic and biomechanical criteria were used to determine whether the osteoconductive performance of plaster of paris would promote the incorporation of the tubular titanium mesh implants used for interbody vertebral fusions., Objectives: To compare the osteogenicity of plaster of paris with that of autogenous iliac crest bone and bone marrow 6 months after they were loaded into tubular titanium mesh cages and implanted as L3-L5 bridges after L4 corpectomies., Summary of Background Data: One of the aims of surgery for vertebral pathology is to stabilize the spine by interbody fusions. The morbidity associated with the use of iliac crest autograft bone for fusion grafts prompted trials using plaster of paris as an osteoconductive substrate., Methods: The total volume of bone that invested the L3-L5 mesh cages after 6 months was quantitated by computed tomography scans. All specimens subsequently were cut into fusion mass segments for biomechanical testing in flexion, extension, compression, and torsion, and then embedded in plastic for sectioning and histomorphometry to determine the trabecular bone volume within the titanium mesh., Results: In each experimental model, implants of plaster of paris were the osteoconductive equal of autogenous iliac crest bone/marrow preparations. The volumes of bone formed around and within the titanium mesh were identical, and the tissues were biomechanically indistinguishable. A partial mechanism was determined by modifying the system for midshaft femoral defects., Conclusions: In the sheep, a tubular titanium mesh packed with plaster of paris forms an osteoconductive conduit to achieve a biomechanically stable interbody lumbar vertebral fusion.

Annular tear is a major cause of intervertebral disc degeneration that results in disabling back pain. Many of the stresses resulting in this type of lesion are common in the workplace: compression, torsion, compression combined with flexion, and vibration. Age-related disc degeneration begins early in adulthood, and progresses thereafter, altering disc morphology and mechanical properties in ways that predispose to disc herniation, and should not be misconstrued as "old age." Acute trauma may produce disc herniation whether or not there are predisposing factors, such as age-related degeneration, but disc herniation in the absence of acute injury requires the presence of preexisting degenerative changes.

The objective of this research was to determine the efficacy and safety of an experimental instrumentation device designed for transpedicular spinal fixation by evaluating fusion rates and clinical pain and function scores; to determine complication rates associated with the device; and to compare the obtained data with that previously published in the literature. Four hundred forty-two consecutive patients were enrolled in this 4-year, Food and Drug Administration-monitored investigational device exemption trial to undergo surgery for implantation of the device. Eighteen surgeons at 11 nationwide medical centers performed the operations and subsequent evaluations. The study population was derived from three diagnostic categories: degenerative disc disease, multioperated back, and vertebral fracture. The data source consisted of radiographs, clinical examination, and structured forms and questionnaires. Patients were evaluated preoperatively, intraoperatively, and postoperatively at 3, 6, 12, and 24 months. By the 24-month postoperative interval, attrition had reduced the study population to 342 patients, among whom bony fusion was obtained in 91.5%. Pain scores demonstrated a statistically significant improvement in clinical outcome. Intraoperative complications occurred in 21.9% of patients. Of the 442 study patients, 2.9% experienced device-related complications. Moreover, a total of 2,304 screws and bolts were implanted in this patient population. Of these, 0.39% were reported to have fractured. Among the 342 study patients observed during 24 months, the breakage rate of device components (bolt or screw) was 2.63%. These data compare favorably to existing reports of spinal arthrodesis effected with other types of instrumentation and without device implantation. In a 4-year trial, the experimental transpedicular fixation instrumentation produced successful spinal fusion in the majority of our study population, with acceptable complication rates.

Torsional injuries may be a precursor to intervertebral disc degeneration, but published rabbit models indicate a latent time of 6 months. We describe a rabbit model in which instability and disc degeneration appear within 3 months. Sixty-five male New Zealand rabbits underwent presurgical irradiation to inhibit heterotopic bone formation. Control animals then underwent either a soft-tissue release or facetectomy and capsulotomy, whereas experimental animals received surgery and an acute 30 degrees torsional lumbar injury. Capsulotomy, as well as facetectomy without torsion, failed to effect disc degeneration. However, the rabbits that received torsion exhibited clear indications of degenerative disc changes (thinning, increased PLA2 levels, and decreased nucleus pulposus volume) within 60-90 days. The observations associate disc degeneration with a destabilizing acute torsional injury.