Ch. Mazel

Instrumentation rachidienne flexible Twinflex dans les arthrodèses lombaires et lombosacrées — Série de 114 cas avec un recul minimal de 1 an

UNLABELLED The author presents a series of 114 cases of lumbo-sacral fusion with a minimum follow-up of 1 year and a mean of 21.7 months.Since the use of the first transpedicular screws (1963 R. Roy-Camille) spinal instrumentation has considerably eased post-operative care in lumbo-sacral fusion as well as fusion rate. Recently, instrumentation has became more and more rigid. But rigidity has its limits. Pain as well as poor bone grafting frequently occurs eventhough surgery was performed correctly. This is why the author has developed a concept of flexible transpedicular instrumentation. The aims are: - To avoid stress-shielding of the graftsimplify implantation during surgery - Avoid excessive stress on the bone and adjacent disc - Improved short and long term acceptance of instrumentation - Avoid removal of implants. Some elements guided instrumentation design. Low profile - Ease of removal - restricted number of implants and instruments. The system developed is based on transpedicular screws with 2.5 mm rods. Stainless steel was prefered to Titanium because of its flexibility. The mechanical results of the first prospective series of 114 cases are studied. Follow up ranges from 12 to 39 months maximum with an average of 21.7 months. 65% of the patients are female. Age ranges from 14 to 89 years old with an average of 50 years.•Pathologies are : 74 cases of discopathy with or without associated disc, 8 cases of degenerative lumbar scoliosis and 32 cases of spondylolisthesis with 13 cases of isthmus lysis and 19 cases of degenerative spondylolisthesis.During the post operative period patients stand between 24 and 48 hours. Walking is allowed with twill corset during the day for the first 3 months.•Length of fixation: In 32 cases it is a floating arthrodesis (L4-5 18 cases, others 14 cases). In 82 cases sacrum is included in the fusion (L3-S1.15 cases, L4-S1.35 cases, L5-S1 20 cases, others 12 cases).• COMPLICATIONS No infections were seen. No phlebitis or pulmonary embolism.•Mechanical complications: They are analysed with an average follow up of 21.7 months and a minimum of 12 months. Screw fractures: Only one case occured at 4 months post op in a L4-5 isthmic spondylolisthesis. Fusion was still obtained within the usual 6 months. Patient went back to work on the 8 th post op month without further complication 14th month post operative. Rod fractures: Fracture of the rod is the demonstration of a pseudarthrosis when occuring between 8 to 12 months post-op. The average pseudarthrosis rate is 3.5% (4 cases). In this series we used two different size of rods. The first group consists of 65 cases with 2 mm diameter rods. The second group consists of 49 cases with 2.5 mm rods. All the pseudarthroses occured in the first group (4 cases). In the second group with an average follow up of 17.2 month no pseudarthroses occured.In 4 cases (3.5%) revision surgery was necessary. Two cases were related to pseudarthrosis and 2 cases to remove instrumentation.Fusion rate in this first prospective series is 96.5%. Rod failure in the first post operative year is the demonstration of pseudarthrosis. On the reverse non failure is a way of assessing fusion without doubt.This homogeneous series demontrates the ability of flexible fixation to obtain a high rate of fusion and a good medium term acceptibility for the patient. Instrumentation was removed only in two cases at patient request.AbstractThe author presents a series of 114 cases of lumbo-sacral fusion with a minimum follow-up of 1 year and a mean of 21.7 months.Since the use of the first transpedicular screws (1963 R. Roy-Camille) spinal instrumentation has considerably eased post-operative care in lumbo-sacral fusion as well as fusion rate. Recently, instrumentation has became more and more rigid. But rigidity has it’s limits. Pain as well as poor bone grafting frequently occurs eventhough surgery was performed correctly. This is why the author has developed a concept of flexible transpedicular instrumentation. The aims are: — To avoid stress-shielding of the graftsimplify implantation during surgery — Avoid excessive stress on the bone and adjacent disc — Improved short and long term acceptance of instrumentation — Avoid removal of implants. Some elements guided instrumentation design. Low profile — Ease of removal — restricted number of implants and instruments. The system developed is based on transpedicular screws with 2.5 mm rods. Stainless steel was prefered to Titanium because of it’s flexibility. The mechanical results of the first prospective series of 114 cases are studied. Follow up ranges from 12 to 39 months maximum with an average of 21.7 months. 65% of the patients are female. Age ranges from 14 to 89 years old with an average of 50 years.•Pathologies are : 74 cases of discopathy with or without associated disc, 8 cases of degenerative lumbar scoliosis and 32 cases of spondylolisthesis with 13 cases of isthmus lysis and 19 cases of degenerative spondylolisthesis.During the post operative period patients stand between 24 and 48 hours. Walking is allowed with twill corset during the day for the first 3 months.•Length of fixation: In 32 cases it is a floating arthrodesis (L4–5 18 cases, others 14 cases). In 82 cases sacrum is included in the fusion (L3-S1.15 cases, L4-S1.35 cases, L5-S1 20 cases, others 12 cases).•Complications: No infections were seen. No phlebitis or pulmonary embolism.•Mechanical complications: They are analysed with an average follow up of 21.7 months and a minimum of 12 months. Screw fractures: Only one case occured at 4 months post op in a L4–5 isthmic spondylolisthesis. Fusion was still obtained within the usual 6 months. Patient went back to work on the 8 th post op month without further complication 14th month post operative. Rod fractures: Fracture of the rod is the demonstration of a pseudarthrosis when occuring between 8 to 12 months post-op. The average pseudarthrosis rate is 3.5% (4 cases). In this series we used two different size of rods. The first group consists of 65 cases with 2 mm diameter rods. The second group consists of 49 cases with 2.5 mm rods. All the pseudarthroses occured in the first group (4 cases). In the second group with an average follow up of 17.2 month no pseudarthroses occured.In 4 cases (3.5%) revision surgery was necessary. Two cases were related to pseudarthrosis and 2 cases to remove instrumentation.Fusion rate in this first prospective series is 96.5%. Rod failure in the first post operative year is the demonstration of pseudarthrosis. On the reverse non failure is a way of assessing fusion without doubt.This homogeneous series demontrates the ability of flexible fixation to obtain a high rate of fusion and a good medium term acceptibility for the patient. Instrumentation was removed only in two cases at patient request.RésuméLes auteurs présentent une série prospective de 114 cas d’arthrodèses lombaires et lombosacrées qu’ils ont réalisées depuis maintenant plus de 3 ans. Ils présentent les étapes qui les ont conduits à préférer une fixation flexible plutôt que rigide. Ils étudient ensuite les résultats mécaniques de 114 patients. Après un choix initial pour des tiges de 2 mm, ils ont finalement opté pour des tiges de 2,5 mm. Le taux de fusion des arthrodèses est élevé puisqu’il atteint pour l’ensemble de la série 96,5%. L’absence de faillite du matériel au-delà d’un délai post-opératoire de un an est pour eux la certitude de l’obtention de la consolidation osseuse. Au contraire, l’apparition d’une rupture est le signe d’une pseudarthrose qui pourra être traitée dans les meilleurs délais en fonction de son caractère symptômatique ou non.

Biomechanical evaluation of different instrumentation for spinal stabilisation.

The varying problems following arthrodesis of the lumbar spine with rods or plates (too much rigidity for the first and insufficient stability for the second) have led us to conceive another type of material, flexible but with enough stability, to favorise healing of bone graft, and decrease the induced pathology on adjacent levels. An experimental study of three types of material: rigid, semi-rigid and flexible was performed on eighteen fresh cadaver spinal segments without and then with discectomy and corporectomy to find out the various types of behaviour. The flexible device seems more supple than the other materials tested: more mobility, less stiffness. Rising hysteresis is explained by plastic deformation. The semi-rigid device presents strong osseous stresses on the L3 level and a large hysteresis corresponding most likely to a mobility between the screws and plates. The rigid device has less mobility, especially in torsion, ascribed to the transverse connection. The stability is high with a small hysteresis. This is of value for bone loss or instability with displacement of the vertebral body.The second study was a modeling of the flexible device validated by comparison to the experimental study. The strains in the wire were high, decreasing with increasing diameter, but is still lower than the elastic limit. The proximity of the elastic limit may allow plastic deformation of the wire. Howewer less strains were found on the screw fixation but increase with the increase diameter of the wire. The influence of the bone quality on the behavior of the device was demonstrated.RésuméLes douleurs et dégénérescences des niveaux adjacents survenant à la suite d’une arthrodèse du rachis lombaire fixée par des tiges ou des plaques (trop de rigidités pour les unes et une insuffisance de stabilité pour les secondes) ont conduit à la conception d’un autre moyen d’ostéosynthèse, flexible mais avec une stabilité suffisante pour favoriser la consolidation de la greffe osseuse et diminuer les contraintes sur les niveaux adjacents.Un comparaison expérimentale de trois types de matériels : rigide (tiges), semi rigide (plaques), et flexible (Twinflex®) fut effectuée sur des segments lombosacrés (prélevés sur 18 cadavres frais), présentant une discectomie ou une corporectomie.Le Twinflex semble plus souple, plus mobile et moins rigide mais avec un risque de plastification (Hystérésis). La plaque présente des contraintes importantes à la partie supérieure et une importante mobilité visplaque (hystérésis). Les tiges sont peu mobiles notamment en torsion, ceci étant lié à la connection transverse, avec une bonne stabilité (corporectomie).Une étude en modélisation du Twinflex® fut validé par comparaison à l’expérimentation. Les contraintes furent trouvées basses sur les vis mais élevées dans les liaisons intervétébrales et peu éloignées de la limite élastique avec le risque de plastification si le diamètre est petit. L’application clinique pourra confirmer ou infirmer le résultat sur la greffe osseuse et l’état des disques voisins.

Predictive value of magnetic resonance imaging in lumbosacral fusion decision making. A case report

Study design: A case report of a L4-5 Modic I discopathy and its post operative clinical and MRI outcome emphazise importance of adjacent disc pre operative assessement.Objective: To assess the need of a correct strategy in lumbosacral fusion decision making.Summary and background data: Modic classification is well known but evolution and relations between the three different stages is not well documented.Methods: A L4-5 fusion performed with Titanium instrumentation enables to document a Modic I stage becoming Modic II after successfull fusion. In the mean time the upper adjacent disc L3-4 Modic III deteriorated in Modic I. A new fusion L3-Sacrum enabled to document the same outcome L3-4 Modic I becoming after successfull fusion Modic II.Result: this specific case demonstrates twice the efficiency of postero lateral fusion in the treatment of discopathy. Modic II stage assessing local stability correlated in our case to good clinical evolution. It also demonstrates the risk of adjacent disc failure in case of Modic I image.Conclusion: M.R.I. pre operative finding needs to be taken in account in fusion decision making. Discopathy can be cured by successful postero lateral fusion. Thus anterior intervertebral fusion or postero lumbar interbody fusion is not mandatory as demonstrated twice in this specific case. Levels of fusion needs correct assessement and can explain poor results.

Instrumentation rachidienne flexible Twinflex dans les arthrodèses lombaires et lombosacrées — Série de 114 cas avec un recul minimal de 1 an@@@Lumbar and lumbo-sacral fusion using Twinflex devices in 114 cases with minimal follow-up of 1 year

UNLABELLED The author presents a series of 114 cases of lumbo-sacral fusion with a minimum follow-up of 1 year and a mean of 21.7 months.Since the use of the first transpedicular screws (1963 R. Roy-Camille) spinal instrumentation has considerably eased post-operative care in lumbo-sacral fusion as well as fusion rate. Recently, instrumentation has became more and more rigid. But rigidity has its limits. Pain as well as poor bone grafting frequently occurs eventhough surgery was performed correctly. This is why the author has developed a concept of flexible transpedicular instrumentation. The aims are: - To avoid stress-shielding of the graftsimplify implantation during surgery - Avoid excessive stress on the bone and adjacent disc - Improved short and long term acceptance of instrumentation - Avoid removal of implants. Some elements guided instrumentation design. Low profile - Ease of removal - restricted number of implants and instruments. The system developed is based on transpedicular screws with 2.5 mm rods. Stainless steel was prefered to Titanium because of its flexibility. The mechanical results of the first prospective series of 114 cases are studied. Follow up ranges from 12 to 39 months maximum with an average of 21.7 months. 65% of the patients are female. Age ranges from 14 to 89 years old with an average of 50 years.•Pathologies are : 74 cases of discopathy with or without associated disc, 8 cases of degenerative lumbar scoliosis and 32 cases of spondylolisthesis with 13 cases of isthmus lysis and 19 cases of degenerative spondylolisthesis.During the post operative period patients stand between 24 and 48 hours. Walking is allowed with twill corset during the day for the first 3 months.•Length of fixation: In 32 cases it is a floating arthrodesis (L4-5 18 cases, others 14 cases). In 82 cases sacrum is included in the fusion (L3-S1.15 cases, L4-S1.35 cases, L5-S1 20 cases, others 12 cases).• COMPLICATIONS No infections were seen. No phlebitis or pulmonary embolism.•Mechanical complications: They are analysed with an average follow up of 21.7 months and a minimum of 12 months. Screw fractures: Only one case occured at 4 months post op in a L4-5 isthmic spondylolisthesis. Fusion was still obtained within the usual 6 months. Patient went back to work on the 8 th post op month without further complication 14th month post operative. Rod fractures: Fracture of the rod is the demonstration of a pseudarthrosis when occuring between 8 to 12 months post-op. The average pseudarthrosis rate is 3.5% (4 cases). In this series we used two different size of rods. The first group consists of 65 cases with 2 mm diameter rods. The second group consists of 49 cases with 2.5 mm rods. All the pseudarthroses occured in the first group (4 cases). In the second group with an average follow up of 17.2 month no pseudarthroses occured.In 4 cases (3.5%) revision surgery was necessary. Two cases were related to pseudarthrosis and 2 cases to remove instrumentation.Fusion rate in this first prospective series is 96.5%. Rod failure in the first post operative year is the demonstration of pseudarthrosis. On the reverse non failure is a way of assessing fusion without doubt.This homogeneous series demontrates the ability of flexible fixation to obtain a high rate of fusion and a good medium term acceptibility for the patient. Instrumentation was removed only in two cases at patient request.AbstractThe author presents a series of 114 cases of lumbo-sacral fusion with a minimum follow-up of 1 year and a mean of 21.7 months.Since the use of the first transpedicular screws (1963 R. Roy-Camille) spinal instrumentation has considerably eased post-operative care in lumbo-sacral fusion as well as fusion rate. Recently, instrumentation has became more and more rigid. But rigidity has it’s limits. Pain as well as poor bone grafting frequently occurs eventhough surgery was performed correctly. This is why the author has developed a concept of flexible transpedicular instrumentation. The aims are: — To avoid stress-shielding of the graftsimplify implantation during surgery — Avoid excessive stress on the bone and adjacent disc — Improved short and long term acceptance of instrumentation — Avoid removal of implants. Some elements guided instrumentation design. Low profile — Ease of removal — restricted number of implants and instruments. The system developed is based on transpedicular screws with 2.5 mm rods. Stainless steel was prefered to Titanium because of it’s flexibility. The mechanical results of the first prospective series of 114 cases are studied. Follow up ranges from 12 to 39 months maximum with an average of 21.7 months. 65% of the patients are female. Age ranges from 14 to 89 years old with an average of 50 years.•Pathologies are : 74 cases of discopathy with or without associated disc, 8 cases of degenerative lumbar scoliosis and 32 cases of spondylolisthesis with 13 cases of isthmus lysis and 19 cases of degenerative spondylolisthesis.During the post operative period patients stand between 24 and 48 hours. Walking is allowed with twill corset during the day for the first 3 months.•Length of fixation: In 32 cases it is a floating arthrodesis (L4–5 18 cases, others 14 cases). In 82 cases sacrum is included in the fusion (L3-S1.15 cases, L4-S1.35 cases, L5-S1 20 cases, others 12 cases).•Complications: No infections were seen. No phlebitis or pulmonary embolism.•Mechanical complications: They are analysed with an average follow up of 21.7 months and a minimum of 12 months. Screw fractures: Only one case occured at 4 months post op in a L4–5 isthmic spondylolisthesis. Fusion was still obtained within the usual 6 months. Patient went back to work on the 8 th post op month without further complication 14th month post operative. Rod fractures: Fracture of the rod is the demonstration of a pseudarthrosis when occuring between 8 to 12 months post-op. The average pseudarthrosis rate is 3.5% (4 cases). In this series we used two different size of rods. The first group consists of 65 cases with 2 mm diameter rods. The second group consists of 49 cases with 2.5 mm rods. All the pseudarthroses occured in the first group (4 cases). In the second group with an average follow up of 17.2 month no pseudarthroses occured.In 4 cases (3.5%) revision surgery was necessary. Two cases were related to pseudarthrosis and 2 cases to remove instrumentation.Fusion rate in this first prospective series is 96.5%. Rod failure in the first post operative year is the demonstration of pseudarthrosis. On the reverse non failure is a way of assessing fusion without doubt.This homogeneous series demontrates the ability of flexible fixation to obtain a high rate of fusion and a good medium term acceptibility for the patient. Instrumentation was removed only in two cases at patient request.RésuméLes auteurs présentent une série prospective de 114 cas d’arthrodèses lombaires et lombosacrées qu’ils ont réalisées depuis maintenant plus de 3 ans. Ils présentent les étapes qui les ont conduits à préférer une fixation flexible plutôt que rigide. Ils étudient ensuite les résultats mécaniques de 114 patients. Après un choix initial pour des tiges de 2 mm, ils ont finalement opté pour des tiges de 2,5 mm. Le taux de fusion des arthrodèses est élevé puisqu’il atteint pour l’ensemble de la série 96,5%. L’absence de faillite du matériel au-delà d’un délai post-opératoire de un an est pour eux la certitude de l’obtention de la consolidation osseuse. Au contraire, l’apparition d’une rupture est le signe d’une pseudarthrose qui pourra être traitée dans les meilleurs délais en fonction de son caractère symptômatique ou non.

Ostéome ostéoïde du pouce : localisation sous-périostée

The case of a 19 year old man with a painful and swollen thumb is reported.Xrays showed a thickening of the cortex of the phalanx, and CT scan led to the diagnosis of osteoid osteoma, showing a typical aspect of a nidus.Pain stopped immediatly after surgical procedure, and the volume of the thumb became normal after 3 monthes.While the hand is not a frequent location for osteoid osteoma, the thumb, especially in the periostal region, is very rare.Contrary to the medullary spongy bone location, Xrays signs are modest, and the CT scan is of great value in diagnosis and specifies the localization.