Flexible memory-alloy instrumentation for unilateral transpedicular kyphoplasty and guided cement augmentation of the thoracic spine.

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.

Hematogenous pyogenic facet joint infection of the subaxial cervical spine. A report of two cases and review of the literature.

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.

Combination drug therapy in treatment of Paget's disease of bone: clinical and metabolic response.

Twenty-seven patients with symptomatic Paget's disease of bone were randomly treated with mithramycin, glucagon, and calcitonin given either alone or in combination. Mithramycin, at a dose of fifteen micrograms per kilogram of body weight per day, proved to be a relatively safe drug and elicited a rapid response with only transient side effects. Calcitonin combined with mithramycin was the most effective therapy.

Efficacy of autotransfusion in spine surgery: comparison of autotransfusion alone and with hemodilution and apheresis.

STUDY DESIGN: Two prospective groups of patients received intraoperative autologous transfusion during reconstructive spine surgery. Before intraoperative autologous transfusion, one group underwent normovolemic hemodilution and apheresis of blood components in the operating room while being prepared for surgery. The allogeneic blood products needed for transfusion by each group were studied and compared with those of a retrospective group of patients receiving conventional transfusion therapy. OBJECTIVES: To determine if a combination of intraoperative autologous transfusion and hemodilution and apheresis decreases reliance on allogeneic blood products and increases autologous transfusions. SUMMARY OF BACKGROUND DATA: Transfusion rates of allogeneic red blood cells, which were unchanged by intraoperative autologous transfusion alone, were lowered when treatment included transfusion of these cells and preoperative autologous deposit. However, donor exposures from transfusions of allogeneic platelets and fresh frozen plasma have not been addressed. METHOD: Preoperative hemodilution and apheresis of autologous red blood cells, fresh plasma, and platelets, performed during induction of anesthesia for spine surgery was followed by intraoperative autologous transfusion using the same supplies. Intra- and postoperative transfusion of blood products to each group were evaluated and compared; allogeneic transfusions were given to a retrospective cohort of patients who received conventional transfusion therapy. RESULTS: Hemodilution and apheresis followed by intraoperative autologous transfusion reduced exposures to individual blood donor products resulting in fewer transfusions and in transfusion of significantly fewer blood products. Intraoperative autologous transfusion alone decreased the number of red blood cells transfused, but required the same donor exposures for fresh frozen plasma and platelet support as the cohort of patients who received conventional transfusion therapy. CONCLUSIONS: A combination of hemodilution and apheresis and intraoperative autologous transfusion significantly decreased transfusion of allogeneic blood products and reliance on preoperative autologous deposit. Autologous transfusion of all blood products was significantly increased.

Hematogenous pyogenic facet joint infection.

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.

Hematogenous pyogenic spinal infections and their surgical management.

STUDY DESIGN: Mainly a retrospective study of 101 cases of pyogenic spinal infection, excluding postoperative infections. Data were obtained through medical record review, imaging examination, and patient follow-up evaluation. SUMMARY OF BACKGROUND DATA: Hematogenous pyogenic spinal infection has been described variously as spondylodiscitis, discitis, vertebral osteomyelitis, and epidural abscess. Recommended treatment options have included conservative methods (antibiotics and bracing) and surgical intervention. However, a comprehensive classification that would aid in diagnosis, treatment planning, and prognosis has not yet been devised. OBJECTIVES: To analyze the bacteriology, pathologic entities, complications, and results of treatment options for pyogenic spinal infection. METHOD: All patients received plain radiographs, gadolinium-enhanced magnetic resonance imaging scans, and bone/gallium radionuclide studies. All patients had tissue biopsies. Bacteriology, hematology, and predisposing factors were analyzed. All patients received intravenous and oral antibiotics. A total of 58 patients underwent surgery. Patient outcomes were correlated with clinical status, with treatment method and, where applicable, with location and nature of epidural compression. Statistical analyses were performed. RESULTS: Spondylodiscitis occurred most commonly with primary epidural abscess, spondylitis, discitis, and pyogenic facet arthropathy, all occurring rarely. Staphylococcus aureus was the main organism. Infection elsewhere was the most common predisposing factor. Leukocyte counts were elevated in 42.6% of spondylodiscitis cases. The erythrocyte sedimentation rate was elevated in all cases of epidural abscess. There were 35 cases of epidural abscess (frank abscess, 29; granulation tissue, 6). Epidural abscess complicating spondylodiscitis occurred most often in the cervical spine, followed by thoracic and lumbar areas. The rate of paraplegia or paraparesis also was highest in cervical and thoracic regions. There were no cases of quadriplegia. All patients with either epidural granulation tissue or paraparesis recovered completely after surgical decompression. Only 18% of patients with frank epidural abscess and 23% of patients with paralysis recovered completely after surgical decompression. Patients with spondylodiscitis who were treated nonsurgically reported residual back pain more often (64%) than patients treated surgically (26.3%). CONCLUSIONS: Pyogenic spinal infection can be thought of as a spectrum of disease comprising spondylitis, discitis, spondylodiscitis, pyogenic facet arthropathy, and epidural abscess. Spondylodiscitis is more prone to develop epidural abscesses in the cervical spine (90%) than the thoracic (33.3%) or lumbar (23.6%) areas. Thecal sac neurocompression has a greater chance of causing neurologic deficit in the thoracic spine (81.8%). Treatment of neurologic deficit caused by epidural abscess is prompt surgical decompression, with or without fusion. Patients with frank abscess had less favorable outcomes than those with granulation tissue, and paraplegia responded to treatment more poorly than paraparesis. Surgery was preferable to nonsurgical treatment for improving back pain.

Plaster of Paris as an osteoconductive material for interbody vertebral fusion in mature sheep.

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.

Pyogenic spondylodiskitis: a radiologic/pathologic and culture correlation study.

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.

A dynamic classification of Paget's disease.

A new dynamic classification of Paget's disease is proposed, incorporating both the radiographic phases of bone remodelling and the scintigraphic findings. Osteolytic, mixed and osteoblastic phases are associated with increased scintigraphic activity, while the osteosclerotic phase of remodelling is associated with normal or diminished activity and an osteoblastic radiographic appearance. Abnormal modelling of bone leading to deformity is produced by accelerated apposition or absorption at the periosteal and endosteal envelopes of the bone. In 112 patients with symptoms from Paget's disease, 527 lesions were classified. The most frequent remodelling phase was the mixed one and the most common modelling state was bone expansion with endosteal and periosteal apposition. Of 88 patients treated medically, 12 had lesions which progressed to increased bone formation without a change in modelling, and the active lesions in seven patients became inactive. Prolonged treatment with disodium etidronate led to progressive osteopenia in 11 patients.

Work-related low back injuries caused by unusual circumstances.

Expanding the knowledge of issues that surround work-related injuries allows for the development of more successful work accident prevention policies, treatment and rehabilitation protocols, and education programs. Specifically, clinical observation indicated that many patients did not perceive or report the circumstances of the injury as being part of their regular duties. The objective of this study was to investigate whether unusual activities or circumstances at work played any significant role in the rehabilitation of patients with disabling low back pain. Four hundred thirty-seven patients with severe disabling pain due to work-related injuries and surgery as an option for treatment were studied. The circumstances at the time of the accident were investigated, including demographic data, type of job held at the time of injury, rapport with supervisor, recent cutbacks in job force, and number of highly related injuries. Thirty-three percent of workers were injured while performing their ordinary job duties, with lifting implicated as the most common cause of injury (66%) followed by pushing/pulling (13%). In most patients (67%), the injury occurred under unusual circumstances or activities not normally described in the worker's job routine. This finding has not been previously addressed and implies that physical therapists can improve patient confidence about rehabilitation and returning to work by educating the patients about these circumstances.

Percutaneous transpedicular discectomy and drainage in pyogenic spondylodiscitis.

Spondylodiscitis normally heals itself, but it can cause bone destruction leading to deformity and often pain. Debridement of these infections by percutaneous transpedicular discectomy with access from adjacent caudal pedicles can accelerate natural healing and prevent progression to bone destruction and deformity. We outline this technique and discuss a series of 28 patients treated using a percutaneous transpedicular approach to obtain culture and histopathology specimens, permit drainage and antibiotic irrigation, and provide a channel for granulation tissue to invade the infected space. This procedure is safe and effective, but it is contraindicated for epidural abscess or granulation tissue-induced neurocompression and it is ineffective against extensive bone destruction.

Pathomechanics and clinical relevance of disc degeneration and annular tear: a point-of-view review.

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.

Techniques and pitfalls of cervical lateral mass plate fixation.

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.

The effectiveness of gallium citrate Ga 67 radionuclide imaging in vertebral osteomyelitis revisited.

We investigated the role of gallium citrate Ga 67 scanning in diagnosing spondylodiscitis. Scans of 41 patients with suspected spondylodiscitis showed increased radionuclide uptake in 39 patients; these findings correlated with those of magnetic resonance imaging and were proved by biopsy. Two patients with negative findings on gallium scans had been strongly suspected of having spondylodiscitis; biopsy findings in these patients showed degenerative changes. Thirteen patients had negative cultures, while 22 had polygenic infections and 4 had granulomatous infections. Gallium scanning proved to be 100% sensitive, specific, and accurate. The interrater accuracy was excellent. Follow-up scans were used to track therapeutic progress. We recommend complementary bone and gallium scans in cases of suspected spinal infections. If the scan is positive, a biopsy should be done. If the scans are negative, no further investigation is needed.

Herpes virus infection can cause intervertebral disc degeneration: a causal relationship?

It has been proposed that intervertebral disc degeneration might be caused by low-grade infection. The purpose of the present study was to assess the incidence of herpes viruses in intervertebral disc specimens from patients with lumbar disc herniation. A polymerase chain reaction based assay was applied to screen for the DNA of eight different herpes viruses in 16 patients and two controls. DNA of at least one herpes virus was detected in 13 specimens (81.25%). Herpes Simplex Virus type-1 (HSV-1) was the most frequently detected virus (56.25%), followed by Cytomegalovirus (CMV) (37.5%). In two patients, co-infection by both HSV-1 and CMV was detected. All samples, including the control specimens, were negative for Herpes Simplex Virus type-2, Varicella Zoster Virus, Epstein Barr Virus, Human Herpes Viruses 6, 7 and 8. The absence of an acute infection was confirmed both at the serological and mRNA level. To our knowledge this is the first unequivocal evidence of the presence of herpes virus DNA in intervertebral disc specimens of patients with lumbar disc herniation suggesting the potential role of herpes viruses as a contributing factor to the pathogenesis of degenerative disc disease.

Intervertebral disc changes after 1 h of running: a study on athletes.

The lumbar spines of 25 long-distance runners were examined using an upright magnetic resonance imaging scanner. All volunteer runners were scanned before and after running for 1 h. Scanning was performed with the runners seated upright (neutral), leaning forwards (flexion) and leaning backwards (extension). All measured discs showed a reduction in disc height after 1 h of running. A significant reduction in disc height was observed in all three body positions (neutral, flexion and extension) after 1 h of running. The results showed that, in flexion, extension and neutral positions, intervertebral discs undergo significant strain after 1 h of running. The lowest disc-height reduction was found at the L5 - S1 space in the neutral position; the same space had the highest percentage of disc degeneration.

Early management of complex proximal humeral fractures using the Aequalis fracture prosthesis: a two- to five-year follow-up report.

We reviewed the outcome of 28 patients who had been treated using the Aequalis fracture prosthesis for an acute fracture of the proximal humerus at a mean follow-up of 39.3 months (24 to 63). The mean age of the patients at the time of the fracture was 66.3 years (38 to 80). The mean Constant score was 68.2 (37 to 84) for the operated shoulder, which represented 89.5% of the mean score for the uninjured side (p < 0.001). The quality of the reconstruction as shown on the immediate post-operative radiographs was categorised into three types, anatomical, acceptable, and unacceptable, depending on the position of the tuberosities relative to the prosthetic head and the humeral shaft. Anatomical reconstruction was associated with a higher mean Constant score as well as higher mean values of anterior forward elevation, abduction and external rotation than the other types, but the differences were not statistically significant (p > 0.231). A total of 18 patients had active anterior elevation > or =150 degrees. Their mean active abduction and external rotation were 163.6 degrees and 31.3 degrees, respectively. In seven of the 28 patients, the mean active anterior elevation, abduction and external rotation were 130.7 degrees, 129.2 degrees and 22.8 degrees, respectively. In all, 12 patients were very satisfied with the results, 12 were satisfied, two were dissatisfied and two were disappointed; 26 reported no or only mild pain while only two had moderate pain. In five patients proximal migration of the humeral head was shown on the anteroposterior radiographs of the shoulder. No evidence of loosening was found in any prosthesis.

The pathophysiology of disc degeneration: a critical review.

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.