Aims

The aim of this study was to determine whether early surgical treatment results in better neurological recovery 12 months after injury than late surgical treatment in patients with acute traumatic spinal cord injury (tSCI).

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Lumbar disc prolapse is a frequent indication for surgery. The few available long-term follow-up studies focus mainly on repeated surgery for recurrent disease. The aim of this study was to analyze all reasons for additional surgery for patients operated on for a primary lumbar disc prolapse.

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The outcome following the development of neurological complications after corrective surgery for scoliosis varies from full recovery to a permanent deficit. This study aimed to assess the prognosis and recovery of major neurological deficits in these patients, and to determine the risk factors for non-recovery, at a minimum follow-up of two years.

During the last decade or more, the anchors used for instrumentation in scoliosis surgery are predominantly transpedicular screws, according to Suk. The long term radiographical feature of screw fixation after scoliosis surgery is not previously studied. A consecutive series of 81 cases with AIS operated on with an all screw construct has been studied by means of low dose CT postoperatively and at 2 years postoperatively. There were 67 females and 14 males, with a mean age of 18.3 ± 3 years. In 26 / 81 (32 %) there were signs of loosing of one or more screws, at a maximum 3 screws. We observed loosened screws in the upper thoracic region in 16 cases, in the thoracolumbar 6 and in lumbar area in 4. Mean pre-op Cobb angle was 56 in cases of loosening and 53 of intact screw fixation (n.s.), the correction rate was 69% in loosened vs 70% among intact screws (n.s.). In males there were signs of loosening in 8/14 (57%) and in females 18/67 (27%). Among cases with loosening, 14% had suboptimal screw positioning postoperatively, in intact cases it was observed in 11% (n.s.). In the whole group there were signs of suboptimal screw positioning 12%. Clinically, 1 case had a loosened L4 screw replaced; and at all 21/26 had no complaints and 5/26 reported minor pain or discomfort. 1/26 had a minor proximal junctional kyphosis about 10°, in 3/26 there was a pull-out of some few mms. With plain radiography loosening could be observed in 11/26 cases; 5 were in the lumbar region. In a consecutive series of 81 adolescents with idiopathic scoliosis who had underwent scoliosis surgery according to Suk, one third showed, 2 years after the intervention, some minor screw loosening, assessed by low dose CT. One patient had one lumbar screw replaced and only 5 patients reported minor discomfort. Males were more prone to develop screw loosening

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Spinal fusion remains the gold standard in the treatment of idiopathic scoliosis. However, anterior vertebral body tethering (AVBT) is gaining widespread interest, despite the limited data on its efficacy. The aim of our study was to determine the clinical efficacy of AVBT in skeletally immature patients with idiopathic scoliosis.

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To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod.

Objective. From our series of 570 Dynesys flexible stabilisation procedures, we studied two prospective series of patients with a minimum one-year follow-up comparing uncoated and hydroxyapatite-coated (HA) screws. Methods. Patients were entered prospectively and followed up at 6 weeks, 3, 6, and 12 months and annually thereafter. Plain radiographs were obtained annually. 58 patients who underwent Dynesys stabilisation with HA coated screws (312 screws) were evaluated. The data was compared with 71 patients who underwent Dynesys stabilisation with non-coated pedicle screws (366 screws). Outcome measures were screw loosening, breakage, implant removal or revision. Follow up was 96 %. Results. In the HA coated group there were five screw breakages in three patients, all affecting S1 screws. There was evidence of loosening in one patient. In the non-HA coated group there were two cases of infection, both had their implants removed. Further 11 patients had screw loosening and required implant removal. There was a significant improvement of anchorage of the HA coated screws. There was no correlation between numbers of level stabilised, or previous surgery and screw loosening. Average time to revision surgery for loosening was 23 months in the non-coated group. Screw fractures occurred at 11 months in the HA coated group. There was no correlation between screw loosening or fracture and gender or age. Conclusions. Change to HA coating was investigated because of high loosening in plain screws. Secure pedicle screw fixation is crucial in dynamic stabilisation as the implant remains under constant load. This study demonstrated the significant improved anchorage of HA coated pedicle screws in dynamic posterior stabilisation of the lumbar spine. HA coating has eliminated the problem of screw loosening irrespective of gender, age, number of level stabilised or whether there was previous lumbar surgery

With the identification of literature shortfalls on the techniques employed in intraoperative navigated (ION) spinal surgery, we outline a number of measures which have been synthesised into a coherent operative technique. These include positioning, dissection, management of the reference frame, the grip, the angle of attack, the drill, the template, the pedicle screw, the wire, and navigated intrathecal analgesia. Optimizing techniques to improve accuracy allow an overall reduction of the repetition of the surgical steps with its associated productivity benefits including time, cost, radiation, and safety.

Cite this article: Bone Joint J 2020;102-B(3):371–375.

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The timing of surgical fixation in spinal fractures is a contentious topic. Existing literature suggests that early stabilization leads to reduced morbidity, improved neurological outcomes, and shorter hospital stay. However, the quality of evidence is low and equivocal with regard to the safety of early fixation in the severely injured patient. This paper compares complication profiles between spinal fractures treated with early fixation and those treated with late fixation.

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It is uncertain whether instrumented spinal fixation in nonambulatory children with neuromuscular scoliosis should finish at L5 or be extended to the pelvis. Pelvic fixation has been shown to be associated with up to 30% complication rates, but is regarded by some as the standard for correction of deformity in these conditions. The incidence of failure when comparing the most caudal level of instrumentation, either L5 or the pelvis, using all-pedicle screw instrumentation has not previously been reported. In this retrospective study, we compared nonambulatory patients undergoing surgery at two centres: one that routinely instrumented to L5 and the other to the pelvis.

Introduction. Halo traction, either on bed or with an accompanying vest is used commonly in Spine surgery, in a variety of clinical situations. The pins are inserted into the skull in safe anatomic zones, using wrenches that are either pre-torqued or exhibit a torque gauge to allow measurable torque application. A torque of 6 – 8 inch pounds is considered ideal for optimal pin tightening. Lesser torques may hypothetically lead to pin loosening and pin track infections, while, excessive torques could lead to pin penetration through the skull. Aim. To test the accuracy and consistency of different torque wrenches used for Halo pin insertion, using a standardised calibration device. Methodology. Three different types of torque wrenches were tested, using the MTS Systems 858 Mini Bionix II calibration device at the School of Engineering laboratory in Cardiff. Each type had four samples. Three more samples of one type, which were already in use at the Spine unit were also tested, making a total sample size of fifteen. The calibration device had a declared average error of 0.5 %. Each torque wrench was tested twenty five times to a pre set value of 6 inch pounds (0.67790897 N-m), resulting in 375 independent observations. Data was recorded electronically and was analysed for error, percentage of error and variability for each device. Results. All wrenches, regardless of model or make, failed to deliver accurate torque at the pre set value on repeated testing. There were both negative and positive errors. The average torque delivered by all wrenches together at a pre set value of 0.67790897 N-m was 0.721337 (+/- 0.116919) N-m. The average percent error for individual wrenches ranged from 4 % to 34 %. When grouped by model, the average percent error (model specific) ranged from 5 % to 29 %. When assessed for consistency, the wrenches revealed a range of values over a minimum of 0.053303 N-m to a maximum of 0.846512 N-m. The variability of all wrenches of one model type was however similar, though not identical. The best performing model had an average variation over 0.165531 N-m while the value for the worst was 0.685794 N-m. Conclusion. Torque wrenches used to tighten Halo pins appear to be neither accurate nor consistent. They deliver torques that are either less than or more than their pre set levels. Different wrenches of one model displayed a similar pattern of variability. While this study does not seek to relate this lack of accuracy and consistency to the development of specific complications like loosening or penetration, it does suggest that extreme care is advisable while using torque wrenches to minimise clinical mishaps

In patients with osteoporosis there is always a strong possibility that pedicle screws will loosen. This makes it difficult to select the appropriate osteoporotic patient for a spinal fusion. The purpose of this study was to determine the correlation between bone mineral density (BMD) and the magnitude of torque required to insert a pedicle screw. To accomplish this, 181 patients with degenerative disease of the lumbar spine were studied prospectively. Each underwent dual-energy x-ray absorptiometry (DEXA) and intra-operative measurement of the torque required to insert each pedicle screw. The levels of torque generated in patients with osteoporosis and osteopenia were significantly lower than those achieved in normal patients. Positive correlations were observed between BMD and T-value at the instrumented lumbar vertebrae, mean BMD and mean T-value of the lumbar vertebrae, and mean BMD and mean T-value of the proximal femur. The predictive torque (Nm) generated during pedicle screw insertion was [-0.127 + 1.62 × (BMD at the corresponding lumbar vertebrae)], as measured by linear regression analysis. The positive correlation between BMD and the maximum torque required to insert a pedicle screw suggests that pre-operative assessment of BMD may be useful in determining the ultimate strength of fixation of a device, as well as the number of levels that need to be fixed with pedicle screws in patients who are suspected of having osteoporosis

We investigated the effects of hydroxyapatite (HA) coating on the purchase of pedicle screws. A total of 23 consecutive patients undergoing lumbar fusion was randomly assigned to one of three treatment groups. The first received uncoated stainless-steel screws, the second screws which were partly coated with HA, and the third screws which were fully coated. The insertion torque was recorded. After 11 to 16 months, 21 screws had been extracted. The extraction torque was recorded. Radiographs were taken to assess fusion and to detect loosening of the screws. At removal, the extraction torques exceeded the upper limit of the torque wrench (600 Ncm) for many HA-coated screws. The calculated mean extraction torque was 29 ± 36 Ncm for the uncoated group, 447 ± 114 Ncm for the partly-coated group and 574 ± 52 Ncm for the fully-coated group. There were significant differences between all three groups (p < 0.001). There were more radiolucent zones surrounding the uncoated screws than the HA-coated screws (p < 0.001). HA coating of pedicle screws resulted in improved fixation with reduced risk of loosening of the screws

We analysed the complications encountered in 102 consecutive patients who had posterolateral lumbosacral fusion performed with transpedicular screw and rod fixation for non-traumatic disorders after a minimum of two years. Of these, 40 had spondylolysis and spondylolisthesis, 42 a degenerative disorder, 14 instability after previous laminectomy and decompression, and six pain after nonunion of previous attempts at spinal fusion without internal fixation. There were 75 multilevel and 27 single-level fusions. There were 76 individual complications in 48 patients, and none in the other 54. The complications seen were screw misplacement, coupling failure of the device, wound infection, nonunion, permanent neural injury, and loosening, bending and breakage of screws. Screw breakage or loosening was more common in patients with multilevel fusions (p < 0.001). Screws of 5 mm diameter should not be used for sacral fixation. Forty-six patients had at least one further operation for one or several complications, including 20 fusion procedures for nonunion. The high incidence of complications is a disadvantage of this technically-demanding method

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During revision procedures for aseptic reasons, there remains a suspicion that failure may have been the result of an undetected subclinical infection. However, there is little evidence available in the literature about unexpected positive results in presumed aseptic revision spine surgery. The aims of our study were to estimate the prevalence of unexpected positive culture using sonication and to evaluate clinical characteristics of these patients.

Purpose. Retrospective review of fusion rates using Grafton DBM/allografts only in AIS. Methods. Medical records of 30 consecutive patients at an average age of 19(18-24)were reviewed. All patients had segmental fixation with dual rod and pedicle screw construct followed by decortication supplemented with matrix strips/allograft chips. Minimum follow up 1.5 years, average of 2 years (1.5-3). First follow up at 3 months postoperatively and than 6 months subsequently. All patients were evaluated using criteria described by Betz et al for “possible pseudoarthrosis” which included persistent back pain, defects in the fusion mass, loosening of pedicle screws, junctional kyphosis and curve progression of more than 10 degrees from initial standing postoperative PA views. There were no infections. Average time to clinically and radiographically evident fusion was 12 months (range 10-16). Radiographically visible unfused facet joints were encountered in 3 patients towards the end of the construct. One patient had extension of the construct to treat junctional kyphosis. Other two remained asymptomatic. None had Progression of deformity. One patient developed pars defect at level below construct and was treated with extension of fusion. Conclusion. Rate of fusion approaches 95% which favourably compares to that in literature. We acknowledge limitations inherent to retrospective design, lack of comparative group and CT analysis, nonetheless the study imparts information on the use of bone substitutes without autografts in a subset of spinal deformity patients

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The aim of this study was to evaluate the outcome of spinal instrumentation in haemodialyzed patients with native pyogenic spondylodiscitis. Spinal instrumentation in these patients can be dangerous due to rates of complications and mortality, and biofilm formation on the instrumentation.

We have studied two matching cohorts of patients treated by Dynesys flexible stabilisation with and without hydroxyapatite (HA) coating of the pedicle screws. From our series of 570 Dynesys procedures, we studied patients with HA coated screws with a minimum one year follow-up. Patients were entered prospectively and followed up at 6 weeks, 3, 6, and 12 months and annually thereafter. Plain radiographs were obtained annually. 58 patients (26 males, 32 females, mean age 55 years at surgery) underwent Dynesys stabilisation with HA coated screws. The data was compared with 69 patients who underwent Dynesys stabilisation with non-coated pedicle screws between 2004 and 2006 (26 male, 53 female, mean age 54 years). Outcome measures were screw loosening, breakage, implant removal or revision. A total of 320 HA coated pedicle screws were inserted. 12 patients were lost to follow-up. 2 patients underwent subsequent level extension, and 2 had their implants removed. There were four screw breakages in three patients, all affecting S1 screws. There was no evidence of screw loosening in any patient. In the non-HA coated group 354 pedicle screws were inserted. 5 patients required revision or subsequent surgery. 12 patients had screw loosening and required implant removal. There was a significant improvement of anchorage of the HA coated screws. Change to HA coating was investigated because of high loosening in plain screws. The improvement has been highly significant. Flexible stabilisation is a better model than fusion because the implant remains under constant load. Disclosure: The authors did not receive any outside funding in support of preparation of this work

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Magnetically controlled growing rod (MCGR) systems use non-invasive spinal lengthening for the surgical treatment of early-onset scoliosis (EOS). The primary aim of this study was to evaluate the performance of these devices in the prevention of progression of the deformity. A secondary aim was to record the rate of complications.

Purpose of Study. To review the medium-term results of the Dynesys stabilisation system used in 113 consecutive patients with discogenic back pain. Methods and Results. 113 consecutive patients with discogenic back pain were treated with Dynesys as the sole intervention. Inclusion criteria included mri proven disc degeneration and an improvement in symptoms following an injection into the disc with local anaesthetic and steroid (spinal disc probing). Patients were followed up for a minimum of 5 years, with outcome measures including SF-36, Oswestry disability index (ODI) and visual pain analogue scores (VPAS). Additional factors reviewed included previous spinal operations, complications, loosening and revision rates with subsequent outcomes. Mean pre-operative ODI was 49.5, SF-36 was 37.6 and VPAS back pain was 60.9. At one year post operatively, these scores were 36.9, 49.4 and 39.8, at five years follow up, the scores were 33.3, 51.8 and 40.1 respectively. We note wide variations in our results. Several significant factors appear to contribute to the outcome of surgery. These include undergoing surgery before the age of 43, no more than 2-level disc degeneration, leg pain less than VPAS 4, and no previous spinal surgery. 19 patients had screw loosening evident on plain film x-rays (4 requiring removal), and 2 patients had screw breakages. 19 patients had implant removal for failure and 2 patients went on to have a fusion procedure. Discussion. Dynesys has a role in the treatment of discogenic back pain. Patient selection is important to outcome and we have identified several pre-operative factors that increase the likelihood of success. The effects are present at 1 year postoperatively and are maintained for at least 5 years. There is a significant screw loosening rate and our series had a 17% revision rate