Randomized clinical trial (level I evidence). To compare the accuracy of non-navigation and Iso-C based navigation in pedicle screw fixation in thoracic spine deformities. Thoracic pedicle screw insertion for spinal deformity correction can be associated with increased pedicle breaches. Iso-C based navigation has been reported to improve the accuracy of pedicle screw placement, but its use in the presence of deformity has not been reported. Twenty-seven patients with scoliosis and 6 patients with kyphosis had a total of 478 thoracic pedicle screws. The average Cobb angle was 58.4° ± 8° (range 50°–80°), and the mean kyphotic angle was 54.6° ± 4° (range 51°–76°). By random allocation, 17 patients had screw insertion under navigation (242 screws) and 16 under fluoroscopic control (236 screws). The 2 groups were compared for accuracy of screw placement, time for screw insertion, and the number of times the C-arm had to be brought into the field. Two independent blinded observers determined accuracy using postoperative computed tomography assessments. There were 54 (23%) pedicle breaches in the non-navigation group as compared to only 5 (2%) in the navigation group (P < 0.001). Thirty-eight screws (16%) in the non-navigation group had penetrated the anterior or lateral cortex compared to 2 screws (0.8%) in the navigation group. Average screw insertion time in the non-navigation group was 4.61 ± 1.05 minutes (range 1.8–6.5) compared to 2.37 ± 0.72 minutes (range 1.16–4.5) in navigation group (P < 0.01). The C-arm had to be moved into the operation field on an average of 1.5 ± 0.25 times (range 1–3) per screw. With single screening data, an average of 11.4 pedicles (range 9–14) could be visualized without necessity to bring the C-arm into operating field again. Iso-C navigation increases accuracy, and reduces surgical time and radiation in thoracic deformity correction surgeries.

An in vivo serial magnetic resonance imaging study of diffusion characteristics in human lumbar discs over 24 hours in healthy volunteers and patients with low back pain. To document the temporal pattern of diffusion in normal human lumbar discs and to study the influence of the vascularity of bone and the status of endplate on diffusion in the normal and degenerate discs. Diffusion is the only source of nutrition to the discs, but no firm data are available on pattern of diffusion in humans. More data on this important subject are required to improve our understanding of disc degeneration and to probe research possibilities for preventing the same. The diffusion pattern over 24 hours following gadodiamide injection was studied in 150 discs (96 normal and 54 degenerate). Signal intensity values for three regions of interest in bone (i.e., vertebral body, subchondral bone, and endplate zone) and seven in the disc were calculated, and normal percentiles of diffusion were derived for these regions. Enhancement percentage for each time period, peak enhancement percentage for each region, and the time taken to achieve peak enhancement percentage (T max) were used to define and compare diffusion characteristics and plot a time-intensity curve to document the 24-hour temporal pattern. The correlation of blood flow of the bone as measured by peak enhancement percentage of vertebral body, the status of the endplate zone as measured by the peak enhancement percentage, and T max of the endplate zone were correlated with the diffusion of the disc. Univariate analysis of variance, multiple comparisons, appropriate tests for significance, and stepwise linear regression analysis were used for analysis of the data using SPSS software. In normal discs, a “diffusion march” from the vertebral body to the center of disc was noted with the SImax being observed at 5 min in the vertebral body and subchondral bone, at 2 hours in the endplate zone, and at 6 hours in the nucleus pulposus. A significant difference in mean peak enhancement percentage was observed between that of the body and the discs in those less than 10 years and those above the age of 20 years (P < 0.001). Alterations in endplate zone produced distinct magnetic resonance imaging signs of disturbance in diffusion, which offered a reliable noninvasive method of identifying endplate cartilage damage. Stepwise linear regression analysis showed that the significant variable influencing diffusion to the center of the nucleus pulposus of the total sample was peak enhancement percentage of endplate zone (R 2 = 0.216; P < 0.001), that of degenerate discs was peak enhancement percentage of endplate zone (R 2 = 0.322; P < 0.001), and that of normal discs (R 2 = 0.324; P < 0.001) was age. Serial postcontrast magnetic resonance imaging studies offer a reliable method of assessing the diffusion of the discs and the functional status of the endplate cartilage. Endplate cartilage damage increases with age and produces considerable changes in diffusion. The present study has described reliable signs by which these damages can be identified in vivo. Aging and degeneration have been shown to be two separate processes by documenting clear-cut differences in diffusion. The present data encourage use of diffusion studies as a noninvasive method to assess the physiologic status of the disc and endplate and to study the effect of drugs, smoking, mechanical loading, exercises, etc. on the physiology of the disc.

A prospective randomized controlled trial. To assess the ability of local vancomycin powder in controlling postoperative infection in spine surgery. Despite improvements through the use of prophylactic systemic antibiotics, surgical site infections remain a significant problem in spine surgical procedures. Various retrospective and prospective studies have reported the efficacy of local application of vancomycin powder in reducing the infection in animal and human studies. However, there were no randomized control trials that reported on its efficacy. Prospective randomized controls of 907 patients with various spinal pathologies were treated surgically during a period of 18 months. The control group received standard systemic prophylaxis only, whereas the treatment group received vancomycin powder in the surgical wound in addition to systemic prophylaxis. Patient demographics, comorbidities, level of spinal pathology, estimated blood loss, nutritional status, and hemoglobin were recorded. Incidence of infection was the primary outcome evaluated. There were 8 infections (1.68%) in the control group (6 instrumented and 2 noninstrumented, 6 deep and 2 superficial) with bacteria cultured in 3 (1 Escherichia coli and 2 Staphylococcus aureus). In the treatment group, 7 infections (1.61%) were observed (6 instrumented and 1 noninstrumented surgical procedures, 6 deep and 1 superficial) with bacteria cultured in 3 (1 Staphylococcus aureus and 2 Klebsiella). No adverse effects were observed from the use of vancomycin powder. Statistically no significant difference was seen in infection rate between the treatment group and control group. The local application of vancomycin powder in surgical wounds did not significantly reduce the incidence of infection in patients with surgically treated spinal pathologies. The use of vancomycin powder may not be effective when incidence of infection is low.

Limb-injury severity scores are designed to assess orthopaedic and vascular injuries. In Gustilo type-IIIA and type-IIIB injuries they have poor sensitivity and specificity to predict salvage or outcome. We have designed a trauma score to grade the severity of injury to the covering tissues, the bones and the functional tissues, grading the three components from one to five. Seven comorbid conditions known to influence the management and prognosis have been given a score of two each. The score was validated in 109 consecutive open injuries of the tibia, 42 type-IIIA and 67 type-IIIB. The total score was used to assess the possibilities of salvage and the outcome was measured by dividing the injuries into four groups according to their scores as follows: group I scored less than 5, group II 6 to 10, group III 11 to 15 and group IV 16 or more. A score of 14 to indicate amputation had the highest sensitivity and specificity. Our trauma score compared favourably with the Mangled Extremity Severity score in sensitivity (98% and 99%), specificity (100% and 17%), positive predictive value (100% and 97.5%) and negative predictive value (70% and 50%), respectively. A receiver-operating characteristic curve constructed for 67 type-IIIB injuries to assess the efficiency of the scores to predict salvage, showed that the area under the curve for this score was better (0.988 (± 0.013 sem)) than the Mangled Extremity Severity score (0.938 (± 0.039 sem)). All limbs in group IV and one in group III underwent amputation. Of the salvaged limbs, there was a significant difference in the three groups for the requirement of a flap for wound cover, the time to union, the number of surgical procedures required, the total days as an in-patient and the incidence of deep infection (p < 0.001 for all). The individual scores for covering and functional tissues were also found to offer specific guidelines in the management of these complex injuries. The scoring system was found to be simple in application and reliable in prognosis for both limb-salvage and outcome measures in type-IIIA and type-IIIB open injuries of the tibia.

Study Design. A prospective multimodal study including clinical, radiological, serial postcontrast magnetic resonance imaging, intraoperative findings, and histopathological study. Objective. To document in vivo, the site of anatomical failure in lumbar disc herniation (LDH). Summary of Background Data. Although in vitro mechanical disruption studies have implicated both the endplate junction (EPJ) and the annulus fibrosus (AF) as the site of failure in LDH, there are no in vivo human studies to document the exact anatomy of failure. Methods. One hundred eighty-one consecutive patients requiring microdiscectomy at a single level formed the study group. The status of the endplate and AF in the operated level (study discs) and the other discs (control) were evaluated by plain radiograph, thin slice computed tomographic scan, plain and contrast magnetic resonance imaging, intraoperative examination, and histopathological analysis. Results. LDH due to EPJ failure (EPJF- type I herniation) was more common (117; 65%) than annulus fibrosis rupture. Herniated discs had a significantly higher incidence of EPJF than control discs (P < 0.0001). The EPJF was evident radiologically as vertebral corner defect in 30 patients, rim avulsion in 46, frank bony avulsions in 24, and avulsion at both upper and lower EP in 4. Thirteen discs with normal EP radiologically had cartilage or bone avulsion intraoperatively. Sixty-four discs (35%) had intact EP of which annular high intensity zone was found in 21 (11%), suggesting a disruption of AF (type II herniation). Postcontrast magnetic resonance image of 20 patients showed dye leak at the EPJ proving EPJF as main cause of LDH. Conclusion. Our study provides the first in vivo evidence that LDH in humans is more commonly the result of EPJF than AF rupture and offers clinical validation of previous in vitro mechanical disruption studies. Future research must focus on the EPJ as a primary area of interest in LDH. Level of Evidence: N/A