Background. It is known that severe cases of intervertebral disc (IVD) disease may lead to the loss of natural intervertebral height, which can cause radiating pain throughout the lower back and legs. To this point, surgeons perform lumbar fusion using interbody cages, posterior instrumentation and bone graft to fuse adjacent vertebrae together, thus restoring the intervertebral height and alleviating the pain. However, this surgical procedure greatly decreases the range of motion (ROM) of the treated segment, mainly caused by high cage stiffness. Additive manufacturing can be an interesting tool to reduce the cage's elastic modulus (E), by adding porosity (P) in its design. A porous cage may lead to an improved osteointegration since there is more volume in which bone can grow. This work aims to develop a finite element model (FEM) of the L4-L5 functional spinal unit (FSU) and investigate the loss of ROM induced by solid and porous cages. Materials and Methods. The Intact-FEM of L4-L5 was created, which considered the vertebrae, IVD and ligaments with their respective material properties. 1. The model was validated by comparing its ROM with that of other studies. Moments of 10 Nm were applied on top of L4 while the bottom of L5 was fixed to simulate flexion, extension, lateral bending and axial rotation. 2. The lumbar cages, posterior instrumentation and bone graft were then modelled to create the Cage-FEMs. Titanium was chosen for the instrumentation and cages. Cages with different stiffness were considered to represent porous structures. The solid cage had the highest modulus (E. 0. =110 GPa, P. 0. =0%) whereas the porous cages were simulated by lowering the modulus (E. 1. =32.8 GPa, P. 1. =55%; E. 2. =13.9 GPa, P. 2. =76%; E. 3. =5.52 GPa, P. 3. =89%; E. 4. =0.604 GPa, P. 4. =98%), following the literature. 3. The IVD was removed in Cage-FEMs to allow the implant's insertion [Fig. 1] and the previous loading scenarios were simulated to assess the effects of cage porosity on ROM. Results. The Intact-FEM presents acceptable ROM according to experimental and numerical studies, as shown by the red line in Figure 2. After insertion, lower ROM values in Cage-FEMs are measured for each physiological movement [Fig. 3]. In addition, highly porous cages have greater ROM, especially in axial rotation. Discussion. Significant reduction of ROM is expected after cage insertion because the main goal of interbody fusion is to allow bone growth. As such, the procedure's success is highly dependent on segmental stability, which is achieved by using cages in combination with bone graft and posterior instrumentation. Furthermore, higher cage porosities seem to affect the FSU. In fact, ROM increases more as the cage modulus approaches that of the cancellous bone (E. canc-bone. =0.2 GPa. 1. ). Next step will be to assess the effects of cage design on the L4-L5 FSU mechanical behavior and stress distribution. To conclude, additive manufacturing offers promising possibilities regarding implant optimization, being able to create porous cages, thus reducing their stiffness. For any figures or tables, please contact the authors directly

The progressive kyphosis and pain in patients with acute thoracolumbar burst fractures treated conservatively so as the recurrent kyphosis after posterior reduction and fixation were associated to disc collapse rather than vertebral body compression. It depends on redistribution of the disc tissue in the changed morphology of the space after fractures of the endplate. The aim of this study is to evaluate the safety and the efficacy of balloon kyphoplasty with calcium phosphate, alone or associated to short posterior instrumentation, in the treatment of acute thoracolumbar burst fractures. Eleven fractures in ten consecutive patients with an average age of 48 years who sustained acute thoracolumbar traumatic burst fractures without neurological deficits were included in this study. The fractures were A1.2 (3), A3.1 (4) and A3.2 (4), according to AO classification. In 7 fractures (A1.2 and A3.1) the kyphopasty was performed alone in order to make the most of efficacy in fracture reduction, anterior and medium column stabilization and, as much as possible, segmental kyphosis correction. In the A3.2 fractures (4), that are unstable, the kyphoplasty was associated to a short posterior instrumentation. To avoid the PMMA long run complications in younger patients, we used a calcium phosphate cement. VAS, SF-36, Roland-Morris questionnaire (RMQ) and Oswestry low back pain disability questionnaire (ODQ) were used to evaluate pain, state of health, functional outcomes and spine disability. To the average follow-up time of 15.5 months (range 8–31) we did not observe statistically significant differences in 7 of 8 SF-36 domains in comparison to general healthy population of same sex and age. At the same follow-up, the spine disability questionnaire showed a functional restriction of 18% (ODQ) and 29,6% (RMQ) being 100% the maximum of disability. No bone cement leakage, no implant failure and no height correction loss were observed in any case. Our data confirm the safety and the efficacy of ballon kyphoplasty with calcium phosphate in the treatment of acute thoracolumbar burst fractures. In this way we can reduce the possible complications resulted from discal space collapse and obtain an early functional restoration. When performed alone, this mini invasive surgical technique offer the advantage of almost immediate return to daily activities. When associated to posterior instrumentation, it decreases the long run complications and allows to reduce the number of stabilized levels, maintaining, in part, the thoracolumbar junction movement

Revision surgery and surgery in previously operated areas are associated with an increased infection risk. In such situations, aggressive surgical debridement may be necessary to control and eradicate the infection. Full thickness defects resulting from such debridement present as a challenge. In most cases, an association of various methods, both surgical and non-surgical, is necessary. Our goal is to describe the use of vaccum dressings as an effective way to deal with extensive and infected dorsolumbar surgical defects, while avoiding the use of myocutaneous flaps. This is a retrospective and descriptive case report based on data from clinical records, patient observation and analysis of complementary exams. We present the case of a 57-years-old obese woman with prior history of double approach with posterior instrumentation and spine arthrodesis (D3 to L4) due to severe dorsolumbar adolescent idiopathic scoliosis. She presented to our consult 42 years after surgery, complaining of lower back pain. Clinical observation and imaging exams demonstrated degenerative disc disease in L5-S1 and L5 anterolisthesis. There was also distal instrumentation breakage (right L4 pedicular screw and contralateral rod) with pseudarthrosis suspicion. Distal instrumentation was removed and no pseudarthrosis was found. Therefore, posterior instrumentation and arthrodesis was performed, from L4 to S1. Surgery went without complications. One week after surgery, patient developed fever and inflammatory signs at the surgical incision, with purulent oozing. Escherichia coli and Proteus mirabilis were identified as the causative agents. Decision was made to remove both lumbar and distal dorsal instrumentation and perform aggressive debridement and lavage, with debridement surgery being repeated twice. Finally, a full thickness defect with approximately 20cm long and 6cm wide resulted from the debridement. A vacuum dressing was then applied, for 5 weeks, with progressive decrease in clinical and analytical inflammatory parameters and wound closure. Four months after the initial surgery, patient was discharged with complete defect closure and reepithelialization. This dressing technique provided a sound solution for defect resolution, as well as an important aid for infection control. It proved to be a viable option in an extensive defect, when surgical flap techniques and traditional dressing techniques could not provide a complete solution

Spinal tuberculosis is one of the most common presentations of skeletal tuberculosis. It is one of the major health issues of developing countries as it is associated with significant morbidity and mortality. Pott's paraplegia is a dreaded complication which can result in permanent neurological deficit, unless treated by timely intervention. We evaluated the efficacy of transpedicular decompression and functional recovery in patients of spinal tuberculosis with neurological deficit. A cohort of 23 patients (15 males and 8 female) with diagnosed spinal tuberculosis and having an average age of 37.5±8.4 years, satisfying our inclusion and exclusion criteria's and giving written informed consent were recruited in our study. All patients were managed by transpedicular decompression and fusion with posterior instrumentation. All the patients were followed up clinically, radiologically and hematologically. Patients were followed up at every six weeks for 4 months and thereafter at three monthly intervals to assess the long term outcomes and complications. Neurological evaluation was done by Frankel grading. Functional outcome was assessed by Visual Analog Score (VAS) and Owestry Disability Index score (ODI score). All the patients were followed for a minimum of 27 months. At the final follow-up, there was a statistically significant improvement in VAS score and ODI score. Out of 23 patients, all except three patients showed neurological recovery. We observed that transpedicular decompression is safe and effective approach for management of spinal tuberculosis as it allows adequate decompression of spinal cord while pedicular instrumentation provides stable spinal fixation and helps in early rehabilitation

Aim of the study was to define the role of surgical stabilization of the spine in treatment of pyogenic spondylitis/diskitis. We restrospectively analyzed patients referred to our department for treatment of pyogenic infection of axial skeleton. In three years period we treated 51 patients with pyogenic infection of axial skeleton, and 46 of them were surgically stabilized by means of posterior instrumentation with or without anterior column reconstruction. Reoperation rate was 7%, and was in all cases associated with failure in reconstruction of anterior column of the spine. This could be achieved either by posterior or by combined approach, and there was no significant difference in perioperative complications in either group of patients. 14 patients presented with initial neurological deficit, and that presented the indication for urgent surgical procedure. We conclude that surgical stabilization of axial skeleton should be always performed in patients with destruction of bone structure. The procedure allows easy achievement of material for bacteriological culture, and precisely targeted antibiotic treatment, and at the same time results with a stable spine, therefore allowing early rehabilitation of these patients. Though neurological deficit presents the indication for urgent decompression of neural structures, we emphasize the importance of reconstruction of all three columns of the spine in all circumstances

Nowadays many new minimally invasive techniques are experienced to perform lower lumbar interbody fusion in attempt to decrease the complications related to open anterior approach. AxiaLIF (axial lumbar interbody fusion) system is a percutaneous transacral approach that exploits the virtual presacral retroperitoneal space to perform annulus-sparing discectomy and interbody instrumented fusion of lower lumbar disc spaces. Additioning posterior percutaneous instrumentation, a robust axial construct is placed which restores disc height, sagittal balance and lordosis with minimal muscle dissection, blood loss and postoperative pain. Via fluoroscopically-guided approach, AxiaLIF procedure creates a presacral retroperitoneal corridor in the midline through a paracoccigeal skin incision of 2-3 cm. This space is void of neuro-vascular major elements. A safe working cannula is put in and docked in the S1-S1 entry level and a transacral channel is realized gaining the central space of the disc. A 360° annulus-sparing radial discectomy is performed with special cutters even in case of collapsed disc space and the bone graft is inserted. The following screwing of AxiaLIF rod restores disc height via distraction if necessary, decompresses the neural foramen indirectly and undertakes instantaneous rigid fixation of adjacent vertebral bodies. Using the same incision point and trajectory through the presacral space as AxiaLIF, it is possible to realized a similar procedure L4-S1 vertebral fusions called AxiaLIF 2L. Between february 2009 and may 2010 25 patients (16F:9M) affected by degenerative disc disease (17) and grade 1 or 2 spondylolisthesis (8) were included in this study. Evaluated outcomes were the amount of bleeding, the presence of presacral hematoma, the functional recovery time, the surgery time rate, the x-ray time rate, the complication rate (infection, pelvic visceral injury, postoperative pain). 21 of 25 patients underwent AxiaLIF L5-S1 procedures, 4 of these with a stand alone implant and 17 followed by posterior instrumentation. In the remaining 4 patients, a AxiaLIF 2L L4-S1 procedures is performed. 4 of 25 patients had a perioperative suction drenage. Mean operative time for L5-S1 AxiaLIF procedure was 49 minutes. A 2. nd. p.o.d. CT pelvic scan of undrained and drained groups showed a mean presacral hematoma of 45 cc and 17 cc respectively reduced one month later to a mean value of 19 cc and 3 cc. Hemoglobin rate mainly reduced of 1,7 g/dL between pre and postoperative time. At one month all patients improved their quality of life significantly but one had a gluteal pain. No patient had perioperative infections or pelvic visceral injuries or required blood transfusions. This study seems to assess that AxiaLIF procedure is a minimally invasive lower spine techique actually. The presacral hematoma presence seems to have no side effect and it may be prevented by perioperative drainage. More large studies are needed to confirm our results

Introduction. Pedicle subtraction osteotomy is a powerful technique for correcting sagittal imbalance in ankylosing spondylitis. There has been significant perioperative morbidity associated with this technique in the peer review literature. We present the Royal National Orthopaedic Hospital experience with a single surgeon retrospective study that was conducted to evaluate the outcomes in patients who underwent lumbar pedicle subtraction osteotomy for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis. Method. Twenty seven patients underwent a lumbar pedicle subtraction osteotomy and adjacent level posterior instrumentation between 1995 and 2010. There were 18 males and 9 females in the study. Events during the peri-operative course and post-operative complications were recorded. The radiological outcome and patient satisfaction were analysed with mean follow-up of one and a half years. Results. The mean operative time was three and half hours and the mean blood loss was 2290mls. Final follow-up radiograph showed an increase in lumbar lordosis angle from 17 degrees to 45 degrees. The sagittal imbalance improved by 85mm with the operation. Complications included loosening in two patients, one transient neurologic deficit and one infective non-union occurred overall. There were no mortalities from the surgery. Two patients developed junctional kyphosis and required a repeat operation. There was an improvement in the Oswestry Disability Score from a mean of 29 to 16 after the surgey. All (100%) of the patients were satisfied with the results of the procedure and would recommend the surgey to others. Conclusion. The study shows that pedicle subtraction extension osteotomy is effective for the correction of kyphotic deformity in ankylosing spondylitis

Background. The incidence of scoliosis is 2/1000 population in the UK with 80% being idiopathic. In the Royal Victoria Hospital, Belfast there are approximately 25 scoliosis operations per year, the majority are for idiopathic causes and are limited to posterior instrumentation and fusion. It is current practice in this hospital to use a cell salvage machine for every case managed by nursing staff. Objective. To ascertain the requirement for and the economical viability of cell salvage during posterior instrumented scoliosis surgery. Method. Retrospective study looking at 35 charts of patients who had undergone scoliosis surgery (4 were excluded – 3 fracture patients and 1 patient aged 59). We looked at pre-operative haemoglobin, intra-operative blood loss and the need for post-operative transfusion. Results. Average age of patient 15.4 years; 28/31 causes were idiopathic; average blood loss 1282 mls (only 11 charts had it recorded); average pre-operative Hb 13.9; 7 patients required transfusion, 3 of which received cell salvaged blood only (average volume of cell salvaged blood was 148mls) and 2 out of 3 patients with neuromuscular disorders required blood transfusion. To make cell salvage economically viable it has been calculated that approximately 400 cases need to be performed– in our unit this would equate to 16 years assuming each patient yielded 1 unit of blood. Conclusion. This study does not support the routine use of a Cell Saver in posterior instrumented fusion scoliosis surgery in the population group. However, in patient with underlying neuromuscular and congenital abnormalities it may be viable

Despite many new methods with preoperative or intra-operative assistance to improve the accuracy of leg alignment, traditional intramedullary (IM) method of bone cutting is still the most commonly used. Traditional TKR using IM guide has more outliers comparing to new computer aided methods, especially in bowing femur which is more prevalent in Asian population. And IM guide could not be used when there is a medullary bony pathology. Avoiding entrance of medullary cavity has been proposed as one of criteria of minimally invasive TKA. We have designed an extramedullary (EM) guide for the distal femoral bone cutting with millimeter to millimeter increment which is compatible with all posterior referencing instrumentation systems. With mechanical line as the guide line on long leg X-ray film taking with the knee and foot facing anteriorly, the amount of distal femoral bone cutting was measured and recorded on computer screen pre-operatively. During surgery, distal femoral cutting was performed using the EM cutting jig for coronal alignment adjustment tool and anterior femoral cortex and a guide post as sagittal alignment guide. We retrogratively compared the post-operation long leg X-ray film of two hundreds patients using IM or EM guides, the mechanical alignment of femoral components were measured in coronal and sagittal planes. The results showed no significant difference in distribution and the ratio of outliers. However, if the bowing of femur is more than 8 degree, the outlier is more in the IM group. We have applied this technique in 8 patients having medullary pathology including plates or nails in femur. All patients got good post-operative limb alignment without the needs of computer assistance device during surgery. In conclusion, the technique is easy and the instrument is simple. The operative time was not prolonged; the medullary cavity was not entered and compatible with the principle of MIS technique. In case of medullary cavity is obstructed, it is cost-effective by using our EM guide comparing to other methods such as CAOS or PSI

Purpose. A change in lumbar lordosis can affect the outcome following lumbar fusion, and intraoperative positioning is a prime determinant of the postoperative lordosis. The purpose of this study is to determine the change in lordosis and sacral slope (SS) following axial lumbar interbody fusion (AxiaLIF). Method. We retrospectively reviewed 81 patients who underwent a 360 lumbar interbody fusion at L4-5/L5-S1 (two-level procedure) or solely at L5-S1 (one-level) for degenerative disc disease and spondylolithesis utilizing the AxiaLIF with posterior segmental instrumentation. For the two-level procedures, 25 patients had the AxiaLIF placed first and 27 had pedicle screws placed first. For the one-level procedures, 11 patients had the AxiaLIF placed first and 18 had pedicle screws placed first. Standing lateral preoperative radiographs were compared to standing lateral postoperative films. Lumbar Cobb angles were measured at L1-S1, L4-S1 and individual lumbar levels. SS was measured for sacral version. Results. Of the 81 patients studied, 29 underwent one-level AxiaLIF, and 52 underwent two-level AxiaLIF. For the two-level population, there were statistically significant changes (P less than 0.05) in Cobb angles pre- vs. postoperative at the L4-S1, L2-3, and L4-5 levels, but none other. The percent lordosis from L4-S1 pre- vs. postoperative was also noted to be significant. The pre- vs. postoperative Cobb angle comparisons for the one-level population were not found to be significant. The percentages having a greater than or equal to 10 degree change in total lordosis and lordosis from L4-S1 in both one- and two-level groups were similar at ∼20%. There was no difference in either group in percentage having a greater than or equal to five degree change at individual lumbar segments although there was a trend at both L5-S1 and the SS towards less change with the pedicle screws placed first. Conclusion. A significant portion of both single and multilevel fusions with AxiaLIF had a statistically significant change at the L4-5 and L4-S1 levels. In general, there is a small decrease in lordosis at the bottom two segments and SS with reciprocal changes at the proximal levels. The percentage of total lordosis from the L4-S1 level decreased significantly in the multilevel group. Roussouly lordosis type three (well-balanced) was relatively protected from change in lordosis. Placing pedicle screws prior to placing the AxiaLIF in one- and two- level procedures may lead to an improved sagittal alignment. Further observation of this cohort will determine if the change in alignment will impact outcomes or accelerate adjacent level disease