To present the results of surgical correction in patients with double or triple thoracic/lumbar AIS (Lenke types 2,3,4) with the use of a novel convex/convex unilateral segmental screw correction technique in a single surgeon's prospective series. We reviewed the medical records and spinal radiographs of 92 consecutive patients (72 female-20 male). We measured scoliosis, thoracic kyphosis, lumbar lordosis, scoliosis flexibility and correction index, coronal and sagittal balance before and after surgery, as well as at minimum 2-year follow-up. SRS-22 data was available preoperatively, 6-month, 12-month and 2-year postoperatively for all patients. Surgical technique. All patients underwent posterior spinal fusion using pedicle screw constructs. Unilateral screws were placed across the convexity of each individual thoracic or lumbar curve to allow for segmental correction. ‘Corrective rod’ was the one attached to the convexity of each curve with the correction performed across the main thoracic scoliosis always before the lumbar. Maximum correction of main thoracic curves was always performed, whereas the lumbar scoliosis was corrected to the degree required to achieve a balanced effect across the thoracic and lumbar segments and adequate global coronal spinal balance. Concave screws were not placed across any deformity levels. Bilateral screws across 2 levels caudally and 1–2 levels cephalad provided proximal/distal stability of the construct. Mean age at surgery was 14.9 years with mean Risser grade 2.8. The distribution of scoliosis was: Lenke type 2–26 patients; type 3–43 patients; type 4–23 patients. Mean preoperative Cobb angle for upper thoracic curves was 45°. This was corrected by 62% to mean 17° (p<0.001). Mean preoperative Cobb angle for main thoracic curves was 70°. This was corrected by 69% to mean 22° (p<0.001). Mean preoperative Cobb angle for lumbar curves was 56°. This was corrected by 68% to mean 18° (p<0.001). No patient lost >2° correction at follow-up. Mean preoperative thoracic kyphosis was 34° and lumbar lordosis 46°. Mean postoperative thoracic kyphosis was 45° (p<0.001) and lumbar lordosis 46.5° (p=0.69). Mean preoperative coronal imbalance was 1.2 cm. This corrected to mean 0.02 cm at follow-up (p<0.001). Mean preoperative sagittal imbalance was −2 cm. This corrected to mean −0.1 cm at follow-up (p<0.001). Mean theatre time was 187 minutes, hospital stay 6.8 days and intraoperative blood loss 0.29 blood volumes (1100 ml). Intraoperative spinal cord monitoring was performed recording cortical and cervical SSEPs and transcranial upper/lower limb MEPs and there were no problems. None of the patients developed neurological complications, infection or detected non-union and none required revision surgery to address residual or recurrent deformity. Mean preoperative SRS-22 score was 3.6; this improved to 4.6 at follow-up (p<0.001). All individual parameters also demonstrated significant improvement (p<0.001) with mean satisfaction rate at 2-year follow-up 4.9. The convex-convex unilateral pedicle screw technique can reduce the risk of neurological injury during major deformity surgery as it does not require placement of screws across the deformed apical concave pedicles which are in close proximity to the spinal cord. Despite the use of a lesser number of pedicle fixation points compared to the bilateral segmental screw techniques, in our series it has achieved satisfactory scoliosis correction and restoration of global coronal and sagittal balance with improved thoracic kyphosis and preserved lumbar lordosis. These results have been associated with excellent patient satisfaction and functional outcomes as demonstrated through the SRS-22 scores

Adolescent idiopathic scoliosis (AIS) is a complex 3D deformity of the spine. Its prevalence is between 2% and 3% in the general population, with almost 10% of patients requiring some form of treatment and up to 0.1% undergoing surgery. The cosmetic aspect of the deformity is the biggest concern to the patient and is often accompanied by psychosocial distress. In addition, severe curves can cause cardiopulmonary distress. With proven benefits from surgery, the aims of treatment are to improve the cosmetic and functional outcomes. Obtaining correction in the coronal plane is not the only important endpoint anymore. With better understanding of spinal biomechanics and the long-term effects of multiplanar imbalance, we now know that sagittal balance is equally, if not more, important. Better correction of deformities has also been facilitated by an improvement in the design of implants and a better understanding of metallurgy. Understanding the unique character of each deformity is important. In addition, using the most appropriate implant and applying all the principles of correction in a bespoke manner is important to achieve optimum correction.

In this article, we review the current concepts in AIS surgery.

Cite this article: Bone Joint J 2018;100-B:415–24.

Introduction. Longstanding complex muliplanar foot deformities represent a significant challenge. The traditional surgical techniques involve excessive dissection and excision of large bony wedges or modifications of the triple fusion to correct the deformity. The majority of the reports in the literature present collective data on different deformity patterns and also mix paediatric and adult patients, even with multiple correction techniques. The aim of this study was to evaluate the clinical, radiological and functional outcomes of the gradual correction of a single common deformity pattern of equino-cavo-varus using a single correction technique of the V-osteotomy and the Ilizarov frame. Material and methods. We present prospectively collected data on 40 feet in 35 adult patients with stiff longstanding equino-cavo-varus deformity. All patients had a V-osteotomy and gradual correction using an Ilizarov frame, with a mean follow-up of 20 months. We collected the American Orthopaedic Foot and Ankle Scocity score (AOFAS), the Foot and Ankle Disability Index (FADI) and a Visual Analogue Pain score (VAS) for all ptients preoperatively and between 1 and 2 years following frame removal. Results. In 33 patients (38 feet) a stable plantigrade foot was achieved with significant improvement in the gait and the foot alignment. The mean equinus, heel varus and metatarsus adductus improved significantly as measured on x-rays. The mean AOFAS score improved from 38.2 to 73.2, the mean FADI improved from 51.1 to 70.6 and the mean VAS improved from 4.5 to 0.5. Pin-site infection was encountered in 7 feet, premature consolidation in 2 feet and undercorrection in 4 feet. In 2 patients the correction had to be stopped. Conclusion. The results of this report on a single deformity pattern of equino-cavo-varus support the use of this technique for the management of these challenging cases, as a safe, versatile and powerful tool with predictable outcome

Aims

Historically, patients undergoing surgery for adolescent idiopathic scoliosis (AIS) have been nursed postoperatively in a critical care (CC) setting because of the challenges posed by prone positioning, extensive exposures, prolonged operating times, significant blood loss, major intraoperative fluid shifts, cardiopulmonary complications, and difficulty in postoperative pain management. The primary aim of this paper was to determine whether a scoring system, which uses Cobb angle, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and number of levels to be fused, is a valid method of predicting the need for postoperative critical care in AIS patients who are to undergo scoliosis correction with posterior spinal fusion (PSF).

In this work we report our experience, which began in 1981, with 200 patients in the correction of complex deformities (rotational and angular) of the inferior limbs by using the IIizarov method. In our case histories, we demonstrate the advantages of treatment of complex deformities using correction techniques such as epiphysiodesis operations performed in open surgery access or by using percutaneous stapling or osteotomic corrections, which in our experience are only indicated in single plane lower limb deformities. On the other hand, we demonstrate the complete validity of the IIizarov method in the progressive correction of the multi-planar deformities. Such methods allow progressive correction of the deformities in three different spatial planes, resulting, in addition to the possible improvement in the angular defects, in the simultaneous correction of the torsional defects. The critical analysis of our experience also demonstrates the possible complications inherent in the IIizarov method and which have been subdivided into further and greater complications, such as in the acute treatment of serious deformities (joint stiffness, nerve paralysis, and deep pin track infection) and in minor complications (superficial pin track infection)

In the correction of hallux valgus, there are many different treatments with the aim to resume angular values I MF (metatarsal-phalangeal), I IM (intermetatarsal), PASA (proximal articular set angle), sesamoid position, to improve transferring metatarsal pain and the aesthetics of the forefoot. From November 2001 to November 2003, in the 1. st. Clinica Ortopedica at Bari University, 40 patients were treated for hallux valgus (nine males and 31 females). The age ranges from 17 to 82 years of age (median age: 50 years). The correction technique is based on a distal metatarsal osteotomy (modified Chevron techniques) and fixation with ‘hallux splint’ interfragmentation dynamic and compression device (Waldemar Link GmbH & Co Hamburg, Germany). This technique give intra-operative stability of the osteotomy, giving free weight-bearing from the beginning in the post-operative phase and the complete resumption of daily activities in a short period of time. At a median follow-up of 2 months, a significant improvement in the angular values is shown by radiological evaluation. Therefore, the result shows that this surgical technique is valid in the correcting hallux valgus

Aims

Spinal deformity surgery carries the risk of neurological injury. Neurophysiological monitoring allows early identification of intraoperative cord injury which enables early intervention resulting in a better prognosis. Although multimodal monitoring is the ideal, resource constraints make surgeon-directed intraoperative transcranial motor evoked potential (TcMEP) monitoring a useful compromise. Our experience using surgeon-directed TcMEP is presented in terms of viability, safety, and efficacy.

Aims

The aim of this retrospective study was to compare the correction achieved using a convex pedicle screw technique and a low implant density achieved using periapical concave-sided screws and a high implant density. We hypothesized that there would be no difference in outcome between the two techniques.

Aims

High-grade dysplastic spondylolisthesis is a disabling disorder for which many different operative techniques have been described. The aim of this study is to evaluate Scoliosis Research Society 22-item (SRS-22r) scores, global balance, and regional spino-pelvic alignment from two to 25 years after surgery for high-grade dysplastic spondylolisthesis using an all-posterior partial reduction, transfixation technique.

Aims

To report the surgical outcome of patients with severe Scheuermann’s kyphosis treated using a consistent technique and perioperative management.

Correction of spinal deformities such as those seen in idiopathic scoliosis, are one of the challenging aspects of the spine surgeon’s routine. A significant progress has been made in sense of the surgical approaches, implants design and methods of correction during the last two decades. Since the pioneer conception of Paul Harrington that a scoliotic curve can be corrected by distraction, other methods such as derotation and translation came out as an alternative ways to get a straight and balanced spine. Recently, a new concept of correction for spinal deformities named in-situ contouring, has brought to our attention. This method is based on a 6mm Titanium rod (SCS Eurosurgical Inc.) connected to the spine with a multiple hooks and screws system. The rod is bend according to the curve in the coronal plane and loosely secure with setscrews. Following primary application of the rod, the surgeon begins to bend it manually in situ, in a contrary direction to the curve’s shape. By applying a combination of a sagittal and coronal plane forces, the surgeon is able to achieve a final result of a straight and nicely balanced spine. Methods: The medical records of patients with idiopathic scoliosis, who had surgery during the last three years, were reviewed. Patients, whose operation evolves using of the SCS system, enrolled into the study group. Clinical as well as radiographical data were retrieved from the hospital charts. Curves were classified according to King et al., measurements were taken using the Cobb’s method. Results: There were 10 patients in the study group (7 females, 3 males, mean age: 16.6 years). All curves were primary thoracic from which 9 were type II and only one was type III. Mean pre-operative angle of the primary curve was 56°, mean post-operative angle was 22° with a 61% correction rate. Patients were followed for an average period of 12 months. No complications related to surgery, correction techniques, or neurological status was noted. Conclusions: The in-situ contouring system has no drawbacks compare to other known methods. Our feeling is that this new technique gives the surgeon an ability to achieve the final position of the corrected spine, by a slow and gradual manipulation. This is taking a crucial advantage of the elastic property of the spine in order to get good correction and to avoid neurological complications or hooks pull out

Introduction: One of the important goals of scoliosis surgery is to improve or to prevent deterioration of pulmonary function. There have been many reports on this subject, yet there are a few reports on cases that had surgery by modern multi-hook system. Modern instrumentation can provide better correction; therefore better results on pulmonary function can be expected. The purpose of this study is to analyse post-operative pulmonary function in cases that underwent Isola instrumentarion to scoliosis. Method and Results: There are 130 cases (Male 23, Female 107) who underwent Isola instrumentation to scoliosis from December 1991 to December 1998 and had pulmonary function test pre-operatively and at the time of two-years follow-up. Aetiologies were Idiopathic 119, Congenital 3, Neurofibromatosis 2, Marfan 4, and Others 2. Average age is 15 at the time of operation ranging 10 to 26. One hundred and twenty-six cases had single operation and four cases had two-staged anterior-posterior surgery. VC, %VC, Fev.l.0, % Fev.1.0 were measured pre-operatively and two years post-operatively. Body height correction was done using Kohno’ s equation to obtain % VC. The pre-operative average VC, %VC, Fev.l.0, and %Fev.l.0 were 2.4l, 84.2%. 2.1l, and 85.5% respectively. They were 2.6l, 83.0%. 2.3l, and 87.2% at 2 years postoperatively. Cases were diagnosed according to the change of % VC using a threshold of 10% change. If the change of the %VC is less than 10%. it is diagnosed as unchanged. Thirty cases (23.1%) had decreased %VC, 70 cases (53.8%) unchanged and 21 cases (16.1%) had increased %VC. The cases were divided into four groups according to the pre-operative % VC. Group 1; the pre-operative %VC was less than 60%. Group 2; 60% to 69%, Group3; 70% to 79%. and Group 4; 80% or more. The average pre- and post-operative %VC were 50% and 54% in Group 1, 65.5% and 67.5% in Group 2, 75.4% and 80.5% in Group 3, 94.8% and 90.6% in Group 4. Conclusion: The results showed that a patient can expect to have normal or almost normal VC post-operatively when the pre-operative % VC is larger than 70%. On the other hand, if the pre-operative % VC is less than 60% the chance to have normal or almost normal VC . post-operatively is very little. Therefore, surgery must be done before % VC deteriorates to less than 60%. The goal of scoliosis treatment is three fold; 1) to restore stable, balanced, and stable spine, 2) to have normal pulmonary function, 3) to be emotionally stable. In 61% of the cases the surgical technique applied was conventional method which gave average % correction of 68%. From 1997, a new correction technique using Isola system has been applied. Results at one-year follow-up showed better results. It is my opinion that the treatment of scoliosis should be focused not only to the correction of coronal and sagittal curvature but to the correction of thoracic cage deformity

Fixed flexion deformities are common in osteoarthritic knees that are indicated for total knee arthroplasty. The lack of full extension at the knee results in a greater force of quadriceps contracture and energy expenditure. It also results in slower walking velocity and abnormal gait mechanics, overloading the contralateral limb. Residual flexion contractures after TKA have been associated with poorer functional scores and outcomes. Although some flexion contractures may resolve with time after surgery, a substantial percentage will become permanent. Therefore, it is essential to correct fixed flexion deformities at the time of TKA, and be vigilant in the post-operative course to maintain the correction. Surgical techniques to address pre-operative flexion contractures include: adequate bone resection, ligament releases, removal of posterior osteophytes, and posterior capsular releases. Post-operatively, extension can be maintained with focused physiotherapy, a specially modified continuous passive motion machine, a contralateral heel lift, and splinting

We hypothesised whether MIS techniques confer any benefit when treating thoracolumbar burst fractures. This was a prospective, non-randomised study over the past seven years comparing conservative (bracing:n=27), conventional surgery (open techniques:n=23) and MIS techniques (n=21) for stabilisation and correction of all thoracolumbar spinal fractures with kyphosis of >20. 0. , using Camlok S-RAD 90 system (Stryker Spine). All patients previously had normal spines, sustained only a single level burst fracture (T12, L1 or L2) as their only injury. Age range 18–65 years. All patients in both operatively treated groups were corrected to under 10. 0. of kyphosis, posteriorly only. All pedicle screws/rods were removed between 6 months and 1 year post surgery to remobilise the stabilised segments once the spinal fracture had healed, using the original incisions and muscle splitting/sparing techniques. Patients were assessed via Oswestry Disability Index (ODI) and work/leisure activity status 1 year post fracture. The conservatively treated group fared worst overall, with highest length of stay, poorest return to work/activity, and with a proportion (5/27) requiring later intervention to deal with post-traumatic deformity. 19/27 returned to original occupation, at average 9 months. ODI 32%. Conventional open techniques fared better, with length of stay 5 days, most (19/23) returning to original work/activity, and none requiring later intervention. Average return to work was at 4 months. ODI 14%. MIS group fared best, with shorter length of stay (48 hours), all returning to original work/activity at average 2 months, and none requiring later intervention. ODI negligible. There was no loss of correction in either operatively treated groups. The Camlok S-RAD 90 system is a powerful tool for correction of thoracolumbar burst fractures, and maintains an excellent correction. MIS techniques provide the best outcomes in treating this group of spinal fractures, and offer patients the best chance of restoration to pre-fracture levels of activity

Introduction. We describe our experience with a minimally invasive Chevron and Akin (MICA) technique for hallux valgus correction. This technique adheres to the same principles as open surgical correction but is performed using a specialized high-speed cutting burr under image intensifier guidance via tiny skin portals. Methods. All patients undergoing minimally invasive hallux valgus correction between November 2009 and April 2010 were included in this study and were subject to prospective clinical and radiological review. Patients were scored using the Kitaoka score as well as radiological review and patient satisfaction survey. Surgery was performed under general anaesthetic and included distal soft tissue release, Chevron and Akin osteotomies, with the same indications as for open surgery. All osteotomies were internally fixed with cannulated compression screws. Results. 83 operations were performed on 70 patients (2 male 65 female, mean age 54 years (27-78)). The pre-operative mean HVA was 34° and IMA 14°. Post-operative mean HVA was 9° and IMA 9.5°. Kitaoka score improved significantly at 3-12 months follow-up. There were no delayed or non- s and no osteonecrosis. Six M1 osteotomies moved during the postoperative period (3 feet (2 patients) required further surgery + 3 incomplete corrections without need for further surgery) and the fixation technique was successfully modified to avoid this problem. Mild transfer metatarsalgia was observed in 4 patients. There were 2 superficial wound infections. Cutaneous nerve injuries were noted in 3 feet but none painful. No recurrent deformities observed to date. Overall, 65% patients very satisfied, 29% satisfied, 6% unsatisfied. Discussion. This study suggests that good results can be obtained in forefoot surgery with the MICA technique. We believe this technique may offer advantages for some patients in terms of reduced morbidity and cosmesis. A randomized study is in progress to compare open and minimally invasive techniques

Aims

We present the results of correcting a double or triple curve adolescent idiopathic scoliosis using a convex segmental pedicle screw technique.

Anterior stabilisation has been shown to be superior in the treatment of the lumbar and thoraco-lumbar scoliosis, both in regard to the correction of the curves and to the number of fused vertebrae. Since 1995, with the emergence of third-generation locking devices, we have extended the indication of anterior fixation to double major scoliosis with lumbar predominance, operating exclusively on the lumbar curve and allowing the thoracic curve to correct itself. We report this experience with respect to 12 patients. The patients consisted of 11 girls and one boy, mean age 16.6 years (range 12–29). The mean preoperative Cobb angle was: lumbar: 51° (41–72), dorsal 28° (range 21–45). All patients showed a lateral deviation of the trunk with asymmetry of the lumbar region. Of the 12 patients, 11 received stabilisation by EUROS instruments from D11 to L3 and one from D10 to L3. The mean follow-up is 44 months (range 15–77 months). A vertebral fusion was achieved for 94 % of the spaces (46/49). In the fixation zone, a 72% correction rate was achieved, whereas in the non-treated zone of the dorsal rachis, the rate of spontaneous correction was 32 %. In total the angle loss has been on average 4°. The study assessed the horizontal position of the disk underlying the zone of the arthrodesis; in other words the L3 – L4 disk showed the presence of an average gradient angle of 7° with a range from 0° to 17°. No post-operative complications were observed, but 7 of 12 patients have had immediate and transient sympathectomy after-effects, with a modification of the ipsilateral limb temperature at the level of the instrumental access site. Anterior stabilization of the thoracolumbar curve in double major scoliosis with lumbar predominance seems to be preferred to posterior correction. This technique, by preserving the posterior musculature, makes it possible to save from 1 to 2 disk downwards. In turn, this makes it possible to correct the lateral translation and the realignment of the trunk starting with fusion limited to the lumbar spine. It is imperative to avoid hypercorrection of the thoraco-lumbar curve and even leave a bit of curve in the in situ modelling of the rod. Then the lumbar curve can be balanced with the dorsal curve and avoid an increase in the lumbosacral counter-curve with the risk in of rotatory dislocation in adult age. Since we have started using this technique, we have not had to perform double correction, anterior and posterior, for double major scoliosis with lumbar predominance

Background: Heel valgus and flattening of arch are common in rheumatoid arthritis (RA). The progression of hindfoot valgus deformity results in pain and debilitating disability, and causes the excessive stress on the ankle joint. Subtalar arthrodesis is often indicated in these cases to reduce the pain and to correct the talocalcaneal alignment. However, accurate correction is not easy without bone grafting, because bone defect often appears after correction. Bone grafting is necessary for accurate correction in these cases, but we have avoided it because of following reasons; donor site problem like insufficiency fractures of pelvis, supply limitation of autograft for possible multiple operations during long term disease progression of RA and the lack of bone graft substitutes, which possesses enough osteoconductivity. Now we have developed the interconnected porous calcium hydroxyapatite (IP-CHA) which possesses good osteoconductivity and achieves major incorporation with host bone much more rapid than the other porous calcium hydroxyapatite. So, we evaluated the usefulness of the packing with the newly developed IP-CHA in bone defect after correction of pes planovalgus deformity of RA patients. Methods: The best possible correction of talonavivular alignment and fixation is performed using one cubic hydroxyapatite block (1x1x1cm), staple and Kirschner wire. Then granular IP-CHA is implanted in bone defect existing mainly in talar body, gap of talonavicular joint and sinus tarsi. Six planovalgus feet were treated with subtalar arthrodesis in 4 female RA patients (3; triple arthrodesis, 3; subtalar and talonavicular arthrodesis). The average age was 56.8 years. Angle of internal arch (IA), tibiocalcaneal (TC) angle in modified Cobey’s method, talocalcaneal height (TCH) in standing position were assessed on the basis of the radiographies at just before operation and final follow-up (average 17.5 months, range 7 to 25 months). Results: Mean IA angle was 138.9 degrees pre-operatively and 132.4 at the last follow-up. Mean TC angle was 14.9 degrees pre-operatively and 7.2 at the last follow-up. No collapse or deformity of hydroxyapatite implanted in the bone defect was observed. Conclusion: Our original technique using IP-CHA was shown to prevent from initial sinking or loss of correction. This technique could make it quit easy to correct the malalignment of talocalcaneal joint with regaining of TCH in painful planovalgus deformity of RA patients

Purpose: The risk of injuring the radial nerves during spine instrumentation to correct spinal deformity is well known and accounts for about 50% of the neurological complications associated with this type of surgery. We describe a technique for monitoring the nerve roots during spinal surgery. Radicular monitoring was described by Hormes in 1993. Material and methods: We report a retrospective analysis of 73 procedures for spinal deformity during which the nerve roots were monitored. The series included 27 men and 46 women, mean age 23.9 years (range 4.5–74.9). Forty patients were less than 18 years old. Procedures included posterior arthrodesis (n=65) and anterior arthrodesis (n=8). Indications were: idiopathic scoliosis (n=32), neurological scoliosis (n=21), congenital scoliosis (n=4), spondylolisthesis (n=2) and kyphosis (n=3). The study group included 68 patients (168 roots) with recordings obtained under the required conditions. The routine procedure involved permanent electrophysiological monitoring of muscle activity with a multi-channel electromyograph. We used microwires implanted within the muscle itself for electrodes. Target muscles depended on the position of the planned implants and the topography of the roots likely to be endangered during the surgical procedure or instrumentation. Explored roots were: T12 (n=9), L1 (n=24, L2 (n=40), L3 (n=24), L4 (n=23), L5 (n=11), S1 (n=22). Monitoring prohibited use of curare during anaesthesia. Results: Prior to radicular monitoring, we had had two root injuries (T12 and L3) which resolved spontaneous (n=139). During the study, changes in the radicular signal were observed in seven patients. All signal anomalies triggered a modification of the surgical procedure and no postoperative deficit was observed. Incidents observed concerned congenital scoliosis (n=2), neurological scoliosis (n=2), and idiopathic scoliosis (n=3). Roots involved were L1 (n=1), L2 (n=2), L3 (n=2), L4 (n= 4), i.e. 11/163. Discussion: Continuous intraoperative monitoring of the spinal roots exposed to surgery for spinal deformity enabled us to identify eleven cases of root suffering among 163 recordings. This permanent monitoring system enabled us to immediately modify the surgical procedure and to control and conflict between the instrumentation and the roots or possible stretching during the correction. This technique requires permanent monitoring during the spinal procedure to avoid false negatives. Curare cannot be used. Conclusion: Intraoperative radicular monitoring is an effective way to avoid radicular complications of this type of surgery. The technique is sensitive and allows immediate adaptation of the surgical procedure. It requires close collaboration between the neurophysiologist, the orthopaedic surgeon and the anaesthesiologist

Introduction: In situ contouring is meant to give the shape of the spine to the rod and then the shape of the rod to the spine. Thus, it is used in order to set up the instrumentation as well as to reduce the spinal deformity. This technique was born in 1993, when we presented our first scoliosis correction results (CT scan study of vertebral derotation) with the rod rotation technique during the French SRS (GES). Our great disappointment with the rod rotation technique forced us to try to find a different correction method. Scoliosis is the consequence of vertebral rotation. Each vertebra turns about a different axis which results into a global torsion of the spine. This torsion will yield characteristic modifications. On the frontal x-ray view one can notice the maximum projection of the deformity, usually estimated by means of the Cobb angle, whereas on the sagittal x-ray view a flat back will be observed. Indeed, scoliosis flattens sagittal physiological curvatures. Hyperkyphosis may occur only between two scoliotic curves (two adjacent flat back segments) or in case of vertebral rotation higher than 90° when the sagittal projection corresponds to frontal structures. In this last case, the maximum deformity is projected on the sagittal view. The vertebral rotation will also pull on the ribs, thus creating the rib hump. Classical Surgical Techniques: Nowadays there are several classical correction techniques for scoliosis treatment. Over the last decades, Harrington developed the distraction-compression technique, then Eduardo Luque proposed the spinal translation technique, and latter on Cotrel and Dubousset developed the rod rotation method that revolutionised spine surgery. By pulling on the concave side of the spine, the distraction-compression technique is intended to reduce the deformity shaft while dragging along the apex in a pure translation movement. The distraction is applied mainly onto the flexible segments, far from the apex. Therefore, the apex will hardly modify its relative position with regard to the other vertebrae. Besides, there is a high risk of spinal cord stretching on the concave side at the apex level. Furthermore, this technique is often associated with a high rate of post-operative flat back and requires postoperative cast and brace wear as the fixation remains fragile. Last but not least, the traction technique does not solve the rotation problem. On the contrary, traction increases the torsion forces and leads to higher rotation constraints. The spinal translation used to be performed by means of metallic wires passing under the lamina that were tightened around the rod. This technique of scoliosis correction was based on a totally different correction mechanism with regard to Harrington’s one. Indeed, medialisation of the apex results into a spontaneous increase of the intervertebral gap at the extreme levels of the curve. This distraction is automatic, and as a matter of fact it is impossible to apply it as the wires are sliding on the rod. The problem with spinal translation is that it cannot control rotation, neither with screws nor with hooks. Frontal X rays show that the anterior spine will always be located outside the rods pulling the posterior arch. This technique was improved by Asher and Chopin, who introduced screws and hooks. However it is still very difficult to decide on which side one should work, i.e. concave or convex side. The problem of rotation is still unsolved as anterior spine projection onto the x-rays is still next to and outside the rods. Rod rotation is the most popular technique nowadays as it allows rather good global correction. However, the thoracic correction does not follow the pathology path and therefore has no impact of vertebral rotation. This technique allows only slight adjustments, often very difficult to perform especially in the frontal plane. In 1993, we reviewed 52 scolioses operated with the rod rotation technique. All patients had undergone pre- and post-operative CT scan, so we could estimate the rotation correction. The results were highly disappointing as the vertebral rotation at the LEV (lower end vertebra) decreased of only 2.3°, while at the UEV (upper end vertebrae) level it was 1.1° higher after surgery, and at the apex level it remained almost unchanged (0.4° smaller). In conclusion, correction was obtained by vertebral translation, horizontalisation, forward and backward pushing of the vertebra, without any derotation. Several examples clearly reflected this mechanism, proved by the mobilization of the vertebrae with regard to the aorta. When looking at the path described by the vertebra, one can easily notice that the different techniques described above do not allow to follow the deformity path. Thus, the thoracic vertebra goes frontward and turns to the right. This circular movement has a posterior centre of rotation. Vertebral translation does not follow this path as it moved about the arch cord. The rod rotation performs a circular movement about an anterior centre of rotation. The correction and deformity paths describe an ellipse. We can conclude that these techniques will lead to high constraints within the spine. Hence the risk of neurological structures damage during correction manoeuvres. At the lumbar level, the apex moves backwards and to the left. Thus, it will describe an arch about a posterior rotation centre. The vertebra traction will move along the cord of this arch while the rod rotation will strictly follow the reverse pathology path. As the convex rod is linked to a hook or a screw, it will lead to a combined force of internal traction and anterior push. This convex push increases rotation by turning the screw in the sense of pathologic deformity. Therefore, the projections of the screws on the frontal x-rays will be oriented outside the rod, while the normal axis of the pedicle is about 20° oblique oriented toward the inside. In Situ Contouring: Given these conclusions on the failure of traditional methods, we tried to develop the in situ contouring for a more efficient scoliosis correction. We would like to remind surgeons that the technique was designed to give the shape of the spine to the rod in order to set the instrumentation up, then to give the shape of the rod to the spine in order to reduce the deformity. All surgeons performed in situ rod bending at least once in their practice without being aware of. However, when performing in situ contouring, some security rules have to be strictly respected. First of all, the rod must be free to move, so implants must be closed around the rod but remain unlocked until the correction manoeuvres are finished. The rod mobility will allow the automatic spine stretching/shortening without dangerous constraints. Vertebrae must slide along the rod by means of the implants, i.e. screws and hooks, solidly attached to them. In other words, the spine, i.e. vertebrae, must be mobilised. To do so, the benders must be placed close to the implants. The other reason is to avoid high lever arms that would lead to high risky forces (loads). The correction principles are based on the vertebrae movement in space in order to enable a frontal and sagittal correction while working into the axial plane. To do so, the rod must have specific mechanical features: initial short elastic and long plastic domains. The correction manoeuvres on the rod will modify this mechanical behaviour and at the end of the correction manoeuvres the plastic domain will decrease wile the elastic one will increase. An initially too elastic rod would require stronger manoeuvres with regard to the residual correction, which may present some supplementary risk for neurological structures. The levels to be instrumented are selected as usual, as in situ contouring does not modify rules usually used in order to determine the strategic vertebrae. The strategic vertebrae are selected depending on the information provided by bending tests. Thus all discs that do not open in both directions will be included into the fused segment. Thoracic scoliosis: Similar to the rod rotation, the working rod is concave one in the thoracic spine. In contrast with the rod rotation technique, every second vertebra will be instrumented, going as close as possible from the apex. As neither distraction nor compression is performed, laminar hooks are not compulsory anymore. In our practice, we use pedicular hooks above T10 and screws below T10. The rod will be contoured towards the inside and backwards for all instrumented levels. These manoeuvres will allow the medialisation of the apex while restoring kyphosis. At the same time, these actions will lead to a derotation of the apex. The contouring manoeuvres are performed iteratively starting from the apex towards the limits of the curvature through successive manoeuvres in the frontal plane and in the sagittal plane. Contouring is over when required correction is obtained and when the rod modified its mechanical behaviour and became too elastic to allow further contouring. The apex follows the deformity path. Thus the vertebra moves backwards and towards the inside, describing a circular movement similar to the deformity path in the opposite sense. Therefore, three-dimensional correction of both mild and severe (> 100°) thoracic scolioses. However, the purpose of the surgery should not be to have a straight vertical rod, but to obtain the best possible spinal balance with the best possible correction in the three planes. Lumbar scoliosis: Lumbar scoliosis may also be treated by in situ contouring. In this case, the working rod is the convex one. This rod will be bent towards the inside and forwards, thus enabling the lordosis restoration and the medialisation of the apex. These combine manoeuvres should lead to derotation. However, similarly to the rod rotation technique, forward bending will make the apex move in the pathological direction, thus increasing rotation. Thereby, it is paramount that screws turn simultaneously with the contouring manoeuvres. Only this combination of movements will provide with a three-dimensional correction. To do so, derotation blocks are placed on the screws heads so that the assistant can turn them while the surgeon is performing the forward contouring manoeuvres that will allow lordosis restoration. This mobilization perfectly follows the deformity path and replaces the spine between the rods. This technique may be used both for mild and severe scoliosis correction in the three planes. To facilitate correction and to maintain it on a long term basis, posterior release and posterior fusion may not always enough. In this case, anterior release and grafting may be required. Anterior approach may be facilitated by video assistance. Thoracoscopy will be preferred between T3 and T11, while video assistance is recommended for the thoracolumbar and lumbar regions. Anterior release associated with in situ contouring does provide significant correction especially in severe scoliosis as well as in stiff curvatures in the adult. Three Dimensional Validation in Practice: Theory is nice but validation in practice is compulsory in order to verify our hypotheses. To check the validity of our statements, Raphael Dumas, PhD, performed a biomechanical analysis of the surgical correction by in situ contouring technique. He studied 20 scoliotic patients by means of stereoradiographic three-dimensional reconstruction. The stereoradiographic reconstruction technique is based on the identification of anatomical landmarks on frontal and sagittal x-ray films, previously acquired in a calibrated radiological environment equipped with a 90° turning table. This method provided us with three-dimensional reconstructions of spines allowing for an accurate measurement of vertebral rotations. Indeed, vertebral rotations must be measured in standing position, especially in the pre-operative examination, and has to be expressed in a fixed referential. These requirements could not be met with the traditional methods, i.e. CT scan. Three-dimensional reconstructions also provide us with an axial view of the whole spine, while allowing a comparison between the post-operative and pre-operative vertebral rotations at each level. We also calculated the intervertebral rotation. This rotation is maximum at the end vertebrae levels and minimum at the apex level. It is totally independent from the reference axis as the trunk movement will not alter the relative position of adjacent vertebrae. We actually consider that intervertebral angles are paramount for the estimation of the deformation severity as well as of the obtained correction. In our series (20 scoliotic patients) we observed a maximal rotation at the thoracic apex level (17.3°) and at the lumbar apex one (19°). The correction gain obtained was 11.3° at both levels. The intervertebral rotation had a maximum value at the limit vertebrae levels, i.e. 8.9° for thoracic superior level, 11.3° at the thoraco-lumbar junction and 7.3° at the inferior lumbar level. The correction obtained in these three regions was respectively 7.2°, 8.9° and 6°. We developed a detorsion index that corresponds to the difference between post-operative and pre-operative sums of intervertebral rotations of vertebrae within the organic curvature pondered by the pre-operative sum. The detorsion index at the thoracic level is 52% while at the lumbar level it is 85%. One can note that the thoracic detorsion is quite disappointing. We could consider that the pedicular hook prevents from important detorsion in the thoracic spine, as it will not allow important derotation of vertebrae. This is why we had to design a new pedicular implant that was meant to provide bilateral support during correction manoeuvres. The so called bipedicular implant is linked to the vertebra at the costo-vertebral joint level holds the pedicle on its lateral side. This new implant enables a double action, i.e. posterior traction combined with concave medialisation and convex push. Thus the vertebra moves as a wheel, describing a global movement of derotation. We have used this implant for two years now and we had no particular drawbacks as far. No tolerance problems were noted either. Derotation blocs allow for the combination of rotation movements at the thoracic and lumbar levels while the rod is contoured to reach the best possible curve correction. Conclusion: The in situ contouring has been used for 10 years now. It is not just a physical gesture; it is a whole new philosophy of reduction, a new way of thinking in spine surgery. In situ contouring replaces vertebra in its initial spatial context while replacing the surgeon in the best position to create after thorough reflection on the pathological mechanism. The in situ contouring may be successfully used not only for scoliosis correction but also for other deformities, especially sagittal ones such as hyperkyphosis, fractures, malunions and lumbar degenerative deformities