Outcome of minimally invasive surgery in the management of tuberculous spondylitis

Introduction: With the advancement of instrumentation and minimally access techniques in the field of spine surgery, good surgical decompression and instrumentation can be done for tuberculous spondylitis with known advantage of MIS (minimally invasive surgery). The aim of this study was to assess the outcome of the minimally invasive techniques in the surgical treatment of patients with tuberculous spondylodiscitis. Materials and Methods: 23 patients (Group A) with a mean age 38.2 years with single-level spondylodiscitis between T4-T11 treated with video-assisted thoracoscopic surgery (VATS) involving anterior debridement and fusion and 15 patients (Group B) with a mean age of 32.5 years who underwent minimally invasive posterior pedicle screw instrumentation and mini open posterolateral debridement and fusion were included in study. The study was conducted from Mar 2003 to Dec 2009 duration. The indication of surgery was progressive neurological deficit and/or instability. The patients were evaluated for blood loss, duration of surgery, VAS scores, improvement in kyphosis, and fusion status. Improvement in neurology was documented and functional outcome was judged by oswestry disability index (ODI). Results: The mean blood loss in Group A (VATS category) was 780 ml (330-1180 ml) and the operative time averaged was 228 min (102-330 min). The average preoperative kyphosis in Group A was 38° which was corrected to 30°. Twenty-two patients who underwent VATS had good fusion (Grade I and Grade II) with failure of fusion in one. Complications occurred in seven patients who underwent VATS. The mean blood loss was 625 ml (350-800 ml) with an average duration of surgery of 255 min (180-345 min) in the percutaneous posterior instrumentation group (Group B). The average preoperative segmental (kyphosis) Cobb′s angle of three patients with thoracic TB in Group B was 41.25° (28-48°), improved to 14.5°(11°- 21°) in the immediate postoperative period (71.8% correction). The average preoperative segmental kyphosis in another 12 patients in Group B with lumbar tuberculosis of 20.25° improved to -12.08° of lordosis with 32.33° average correction of deformity. Good fusion (Grade I and Grade II) was achieved in 14 patients and Grade III fusion in 1 patient in Group B. One patient suffered with pseudoarthrosis/doubtful fusion with screw loosening in the percutaneous group. Conclusion: Good fusion rate with encouraging functional results can be obtained in caries spine with minimally invasive techniques with all the major advantages of a minimally invasive procedures including reduction in approach-related morbidity

Application of vibrational microspectroscopy to biology and medicine

Vibrational microspectroscopic (Raman and infrared (IR)) techniques are rapidly emerging as effective tools to probe the basic processes of life. This review mainly focuses on the applications of Raman and IR microspectroscopy to biology and biomedicine, ranging from studies on cellular components in single cells to advancement in techniques for in vitro to in vivo applications. These techniques have proved to be instrumental in studying the biological specimen with minimum perturbation, i.e. without the use of dyes and contrast-inducing agents. These techniques probe the vibrational modes of the molecules and provide spectra that are specific to the molecular properties and chemical nature of the species

Surgical treatment of neurological scoliosis using hybrid construct (lumbar transpedicular screws plus thoracic sublaminar acrylic loops)

In the nineties, most spinal surgeons supported the validity of segmental spine instrumentation, but this procedure has progressively been abandoned because difficult and with a high risk of neurological complications, in favor of the Cotrel-Dobousset (CD). The CD instrumentation is based on segmentation of curves, thus improving the angular correction and actuates sagittal profile. Sublaminar acrylic loops (Universal Clamp) shows the same resistance to stress as steel or titanium alloy sublaminar wires. The simple procedure and the tensioning of the strips allows re-tensioning and progressive correction. The increased contact area, improves corrective forces, thus reducing the risk of laminar fractures. The aim of this study was to verify the validity of this spinal fixation implant in the surgical treatment of a consecutive series of patients affected by neurologic scoliosis. The authors treated surgically 84 patients affected by neurologic scoliosis with an average age of 14 years (range 10–17). Universal Clamps associated with Socore TM spinal assembly, transpedicular lumbar screws and thoracic hooks at the upper end of the curve were used. The etiology of disease was cerebral palsy in 81 cases, Friedreich ataxia in two cases and Aicardi syndrome in one case. The average preoperative angular value was 73° ± 16°. It was implanted a mean of seven Clamps for each procedure (range 5–9). The average percentage of correction was 72%. Mean operative time was 240 ± 30 min with mean blood loss of 1200 ± 400 ml. No intra-operative complications occurred. Mean follow-up was 36 months. At one-year follow-up the mean loss of correction was 7° ± 2° with no re-intervention required. This is the first report on treatment of neurological scoliosis with this hybrid construct (lumbar screws, thoracic acrylic clamps, thoracic hooks at the upper end of the curve). In this group of patients the Universal Clamps technique appeared safe and effective and its mechanical performance is comparable to all-level screws construct. Furthermore, the kyphotic component can be better managed in case of thoracic lordosis. The most important aspect of this technique is a short operative time and low vascular and neurologic risks combined with a satisfying stability in the short-postoperative period. Nevertheless, it is important to value results on a long-term follow-up to analyze correction loss, pseudoarthrosis, and mechanical failure of the strips

Radiological and clinical outcome of screw placement in adolescent idiopathic scoliosis: evaluation with low-dose computed tomography

Posterior corrective surgery using “all pedicle screw construct” carries risk of neurovascular complications. The study aims were to assess the screw placement in patients with adolescent idiopathic scoliosis using CT with low-radiation dose, and to evaluate the clinical outcome in patients with misplaced pedicle screws. CTs of 49 consecutive patients (873 screws, 79% thoracic) were retrospectively evaluated by two independent radiologists. A new grading system was developed to distinguish between lateral, medial and anterior cortical perforations, endplate perforation and foraminal perforation. The grading system is based on whether the cortical violation is partial or total rather than on mm-basis. The overall rate of screw misplacement was 17% (n = 149): 8% were laterally placed and 6.1% were medially placed. The rates of anterior cortical, endplate and foraminal perforation were 1.5, 0.9, and 0.5%, respectively. Lateral cortical perforation was more frequent in the thoracic spine (P = 0.005), whereas other types of misplacement including medial cortical perforation were more frequent on the left and the concave side of scoliotic curves (P = 0.002 and 0.003). No neurovascular complications were reported. The association between the occurrence of screw misplacement and the Cobb angle was statistically significant (P = 0.037). Misplacements exceeding half screw diameter should be classified as unacceptable. Low-dose CT implies exposing these young individuals to a significantly lower radiation dose than do other protocols used in daily clinical practice. We recommend using low-dose CT and the grading system proposed here in the postoperative assessment of screw placement

Evaluation of thoracic pedicle screw placement in adolescent idiopathic scoliosis

Pedicle screw fixation is a challenging procedure in thoracic spine, as inadvertently misplaced screws have high risk of complications. The accuracy of pedicle screws is typically defined as the screws axis being fully contained within the cortices of the pedicle. One hundred and eighty-five thoracic pedicle screws in 19 patients that were drawn from a total of 1.797 screws in 148 scoliosis patients being suspicious of medial and lateral malpositioning were investigated, retrospectively. Screw containment and the rate of misplacement were determined by postoperative axial CT sections. Medial screw malposition was measured between medial pedicle wall and medial margin of the pedicle screw. The distance between lateral margin of the pedicle screw and lateral vertebral corpus was measured in lateral malpositions. A screw that violated medially greater than 2 mm, while lateral violation greater than 6 mm was rated as an “unacceptable screw”. The malpositions were medial in 20 (10.8%) and lateral in 34 (18.3%) screws. Medially, nine screws were rated as acceptable. Of the 29 acceptable lateral misplacement, 13 showed significant risk; five to aorta, six to pleura, one to azygos vein and one to trachea. The acceptability of medial pedicle breach may change in each level with different canal width and a different amount of cord shift. In lateral acceptable malpositions, the aorta is always at a risk by concave-sided screws. This CT-based study demonstrated that T4–T9 concave segments have a smaller safe zone with respect to both cord-aorta injury in medial and lateral malpositions. In these segments, screws should be accurate and screw malposition is to be unacceptable

Benefit and accuracy of intraoperative 3D-imaging after pedicle screw placement: a prospective study in stabilizing thoracolumbar fractures

Internal fixation is the established dorsal standard procedure for the treatment of thoracolumbar fractures. The main problem of the procedure is the false positioning of the pedicle screws. The exact determination of pedicle screws has up to now only been possible through postoperative computed tomography. This study was intended to clarify the diagnostic value of intraoperative 3D scans after pedicle screw implantation in thoracolumbar spine surgery. The direct intraoperative consequences of the 3D scans are reported and the results of the 3D scans are compared with the postoperative computed tomography images. Intraoperative 3D scans were prospectively carried out from June 2006 to October 2008 on 95 patients with fractures of the thoracolumbar spine that have been treated with internal fixation. Screws positions were categorised intraoperatively, screws in relevant malposition were repositioned immediately. A computed tomography of the involved spinal section was carried out postoperatively for all patients. The positions of the pedicle screws were determined and compared in the axial reconstructions of both procedures. Four hundred and fourteen pedicles with enclosed screws were evaluated by the 3D scans. The time needed for carrying out the 3D scan amounts to an average of 8.2 min. Eleven screws (2.7%) in ten patients were primarily intraoperatively repositioned on the basis of the 3D scan evaluation. Two of 95 patients had to have false positions of the screws revised secondarily following evaluation of the computed tomographies. The secondary postoperative revision rate of the patients amounts to 2.1%. In relation to the number of screws, this is a revision rate of 0.5%. The postoperative computed tomographies showed 323 pedicles without cortical penetration by the screws (78.0%). Ninety-one screws penetrated the pedicle wall (22%). It was possible to postoperatively compare the position classifications of 406 pedicle screws. The CT showed 378 correct screw positions, while 28 screws were positioned falsely. On the basis of the 3D scans, 376 of 378 correct positions were correctly assessed. Twenty-one of 28 false positions could be correctly classified. The sensitivity of all 3D scans reached 91.3% and the specificity 98.2%. The position of 97.8% of the pedicle screws was correctly recognised by the intraoperative 3D scan. Nine screws were classified falsely (2.2%). The comparison of the classification results showed significantly higher error findings by the 3D scan in the spinal section T1–10 (P = 0.014). The image quality of the 3D scan correlates significantly with the width of the scanned pedicle, with the body mass index, the scanned spinal section and the extent of the fixation assembly. 3D scans showed a high accuracy in predicting pedicle screw position. Primary false placement of screws and primary neurovascular damage cannot be avoided. But intraoperative evaluation of the 3D scans resulted in a primary revision rate of 2.7% of the pedicle screws and we could lower the secondary revision rate to 0.5%