Introduction: The efficacy and complications of the transarticular screw procedure have been reported by many authors. However, few have reported this procedure for child younger than 10 years old. We have treated two children for atlantoaxial subluxation with transarticular screws, using a soft collar without a halo-vest, and have achieved bone union in good reduced position. Methods/results. Case 1: a 5-year-old boy with mental retardation and cerebellar infarction due to an insufficiency of the vertebral artery resulting in severe atlantoaxial instability. He presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum. He has been treated with transarticular screw and iliac bone graft by Brooks procedure. Case 2: an 8-year-old boy with congenital spondyloepiphyseal dysplasia and a right valgus knee. He, too, presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum, and has been treated with transarticular screw and iliac bone graft by Brooks procedure. In both cases, we used two half-thread cortical screws with a diameter of 2.7mm and a length of 30mm for the transarticular screw procedure. Discussion/conclusion: Rigid external fixation was obtained by Halo-vest. This method, however, would be expected to cause mental stress for the child patient and the family. More rigid internal fixation would be required to resolve this problem. More rigid internal fixation can be obtained with the transarticular screw, and postoperative orthosis can be performed easily, without the need for a Halo-vest

Over 2 years, 14 patients with C1/2 instability underwent posterior transarticular screw fixation. Pathologies included atlanto-axial subluxation in five rheumatoid patients, atlanto-axial rotatory subluxation and an odontoid fracture in two patients with ankylosing spondylitis, nonunion of odontoid fractures in three patients, three transverse ligament injuries and one type-III odontoid fracture. This study aimed to assess the use of transarticular screw fixation in terms of technique, union rates and functional outcomes. All operations were performed on a Relton-Hall frame with a Mayfield clamp and lateral fluoroscopy. The mean age of the eight men and six women was 48 years. The mean operation time was 112 minutes (65 to 225) and mean blood loss was 270 ml (150 to 700). Autologous posterior iliac crest bone graft was used in all patients. The procedure was aborted in one patient because of difficulty with reduction and screw angulation and in another because of excessive bleeding from the drill hole. Alternative fixation techniques were used in these two patients. All patients wore a Philadelphia collar postoperatively until stability was confirmed. The time to radiological union was 8 to 10 weeks. Clinical outcomes revealed full ranges of flexion and extension in most patients, with a 50% decrease in cervical rotation. There were no neurological complications postoperatively. There was implant failure in one patient, with screw breakage evident at follow-up, but this patient went on to union without further intervention. Transarticular screw fixation is an inexpensive, effective and safe technique for management of C1/2 instability

To assess the outcome and safety of transarticular C1–C2 screw fixation. The clinical and radiological outcomes of 15 patients treated with posterior atlanto-axial transarticular screw fixation and posterior wiring was assessed at a minimum follow up of 6 months. Indications for fusion were rheumatoid arthritis in 8 (instability in 6 and secondary degenerative changes in 2), non-union odontoid fracture 4, symptomatic os-odontoideum one, C1–C2 arthrosis one and irreducible odontoid fracture one. Fusion was assessed with plain x-rays including flexion extension films. Twenty nine screws were placed under fluoroscopic guidance. Bilateral screws were placed in 14 patients and a single screw in one patient. This patient had a single screw placed due to the erosion of the contralateral C2 pars by an anomalous vertebral artery. All patients had radiological union. Two screws (7%) were malpositioned; neither was associated with clinical sequelae. No neurological or vascular injuries were noted. Transarticular C1–C2 fusion yielded a 100% fusion rate. The risk of neurological or vascular injury can be minimised by thorough assessment of pre operative CT scans to assess position of the vertebral artery and use of intra operative lateral and AP fluoroscopy

To assess the outcome and safety of transarticular C1-C2 screw fixation. The clinical and radiological outcomes of 15 patients treated with posterior atlantoaxial transarticular screw fixation and posterior wiring was assessed at a minimum follow up of six months. Indications for fusion were rheumatoid arthritis in eight (instability in six and secondary degenerative changes in two), non union odontoid fracture four, symptomatic osodontoideum one, C1-C2 arthrosis one and irreducible odontoid fracture one. Fusion was assessed with plain x-rays including flexion – extension films. Twenty nine screws were placed under fluroscopic guidance. Bilateral screws were placed in 14 patients and a single screw in one patient. This patient had a single screw placed due to the erosion of the controlateral C2 pars by an anomolous vertebral artery. All patients had radiological union. Two screws (7%) were malpositioned, neither was associated with clinical sequelae. No neurological or vascular injuries were noted. Transarticular C1-C2 fusion yielded a 100% fusion rate. The risk of neurological or vascular injury can be minimised by thorough assessment of pre operative CT scans to assess position of the vertebral artery and use of intra operative lateral and AP fluroscopy

Objective: To review the clinical outcome of 37 consecutive patients undergoing C1– C2 transarticular fixation for patients with Rheumatoid Arthritis. Design: Prospective Observational Study. Methods: There were 37 patients at 2 centres. Age range was 37– 82 years. The time since diagnosis to treatment was 2– 23 years. Clinical presentation included suboccipital pain in 26/ 37 patients and neck pain in 29/37 patients. 22 patients had presented with myelopathy ( Ranawat grade II or III A). The preoperative imaging included Plain X Rays, CT scans and MRI scans. All patients underwent C1/ C2 transarticular screws ( Stealth guided) except 4 patients in which an aberrant course of the vertebral artery was identified. Outcome measures: Functional outcome, Complications, Postoperative Neurological Status, Neck Disability index, Myelopathy disability index. Results: 1 patient had died at 12 month followup. Neck pain improved in 22( 75%) of patients by > 5 points on the VAS. Suboccipital pain had improved in all patients. 17 patients (80%) improved following operation on the Ranawat Grading, 2 patient were worse and 3 patients remained the same. > 70% patients reported improvement in neck disability index and > 50% patients reported improvement in myelopathy disability index. Conclusions: C1/ C2 Transarticular fixation with spinal navigation is a safe technique for treating atlantoaxial instability in patients with Rheumatoid Arthritis. This study demonstrates improvement in all domains including neck disability, myelopathy scores and functional outcome

Purpose: The current gold-standard for atlanto-axial fixation is C1-C2 Transarticular Screw (TS) fixation. In certain cases, the complicated nature of vertebral artery injury could make the application of bilateral transar-ticular screws impossible. This study biomechanically compares three atlantoaxial transarticular salvaging fixation techniques. Method: Nine Fresh ligamentous human cervical spine specimens (C0-C4) were thawed and the tissue surrounding the spine, except the ligaments and discs, was carefully removed. Pure moments were applied to skull in increments of 0.5 Nm from 0 Nm to 2.0 Nm with the help of loading arms, nylon strings and pulleys. The specimens were tested in extension (EXT), flexion (FLEX), left lateral bending (LB), right lateral bending (RB), left axial rotation (LR) and right axial rotation (RR) for all the cases. The positions of the LEDs were recorded using an Optotrak Motion Measurement System (Northern Digital, Waterloo, Ontario, Canada) and was converted into three rotations (flexion/extension, lateral bending and axial rotation) using rigid body kinematic principles in relation to the fixed base. The specimens were tested intact and after type II odontoid fracture, were instrumented and tested with three fixation constructs:. C1-C2 TS on right side and C1LMS-C2PS on contralateral side. C1-C2 TS on right side and C1LMS-C2IL on the contralateral side and. C1-C2 TS on right side with sublaminar wire. Results: All of the three instrumented cases significantly reduced motion across C1-C2 segment in all the modes when compared to intact (P< 0.005, two-tailed unpaired t-test at confidence interval of ninety-five percent) except in extension. TS+C1lM+C2PS is significantly stiffer than TS+ Wire only in axial rotation (P< 0.05) and equivalent in flexion/extension (P=0.75/P=0.51) and left/right bending (P=0.22/P=0.58). TS+C1LM +C2PS is equivalent to TS+C1LM+C2IL in all the loading modes (P> 0.05). TS+C1LM+C2IL is significantly stiffer than TS+Wire in axial rotation (P < 0.05) and equivalent in flexion/extension (P=0.93) and left/right bending (P=0.69/P=0.84). Conclusion: This study showed that TS+C1LMS+C2PS fixation is equivalent to TS+C1LMS+C2ILS fixation in all the rotation modes and superior to TS+Wire fixation in axial rotation averaged over all ranges of motion. Also, TS+C1LMS+C2ILS fixation is superior to TS+Wire fixation in axial rotation averaged over all ranges of motion

Aims

The aim of this retrospective study was to compare the functional and radiological outcomes of bridge plating, screw fixation, and a combination of both methods for the treatment of Lisfranc fracture dislocations.

The Lisfranc fracture dislocation of the tarsometatarsal joint (TMTJ) is a complex injury with a reported incidence of 9.2 to 14/100,000 person-years. Lisfranc fixation involves dorsal bridge plating, transarticular screws, combination or primary arthrodesis. We aimed to identify predictors of poor patient reported outcome measures at long term follow up after operative intervention. 127 patients underwent Lisfranc fixation at our Level One Trauma Centre between November 2007 and July 2013. At mean follow-up of 10.7 years (8.0-13.9), 85 patients (66.92%) were successfully contacted. Epidemiological data including age, gender and mechanism of injury and fracture characteristics such as number of columns injured, direction of subluxation/dislocation and classification based on those proposed by Hardcastle and Lau were recorded. Descriptive analysis was performed to compare our primary outcomes (AOFAS and FFI scores). Univariate analysis and multivariate regression analysis was done adjusted for age and sex to compare the entirety of our data set. P<0.05 was considered significant. The primary outcomes were the American Orthopaedic Foot and Ankle Society (AOFAS) Midfoot Score and the Foot Function Index (FFI). The number of columns involved in the injury best predicts functional outcomes (FFI, P <0.05, AOFAS, P<0.05) with more columns involved resulting in poorer outcomes. Functional outcomes were not significantly associated with any of the fixation groups (FFI, P = 0.21, AOFAS, P = 0.14). Injury type by Myerson classification systems (FFI, P = 0.17, AOFAS, P = 0.58) or open versus closed status (FFI, P = 0.29, AOFAS, P = 0.20) was also not significantly associated with any fixation group. We concluded that 10 years post-surgery, patients generally had a good functional outcome with minimal complications. Prognosis of functional outcomes is based on number of columns involved and injured. Sagittal plane disruption, mechanism and fracture type does not seem to make a difference in outcomes

Purpose of study. Transarticular screw fixation offers acceptably high fusion rates but is not possible in 18% of patients due to a high riding vertebral artery. It also requires pre-operative anatomical reduction which is not always possible. The Harms' technique utilises a posterior C1 lateral mass and C2 pedicle screw. This allows easier access due to the angle of drilling and has become an increasingly popular surgical technique. The aim of this study is to review and compare the above techniques with regard to surgery, complications and outcome. Description of methods. This study is a retrospective chart and radiographic review of patients undergoing posterior C1-2 fusion in a single institution in the period 2003 to 2011. The most common aetiology was rheumatoid arthritis and post-traumatic instability. All atlanto-axial instability patients that came to surgery are included in this study, and only cases with less than six months follow-up were excluded. We report on surgical indications, surgical outcomes, complications and radiographic outcomes. Summary of results. No statistically significant differences were found in blood loss (p=0.47) or surgical time (p=0.44) using the Mann-Whitney U test. Complications in patients undergoing transarticular screw fixation included the need to abandon transarticular screws in two cases due to technical difficulty, metalware failure in two cases and intra-operative cerebrospinal fluid leaks in 2 cases. The Harms technique was associated with a single case of cerebrospinal fluid leak. Conclusion. There is no significant difference in surgical time and blood loss between the two techniques. Both are reliable in terms of fusion. The Harms technique offers the advantage of intra-operative reduction and a smaller wound due to the direction of access. The decision to use one or the other is based on the surgeons skill levels, ability to pre-operative reduce the joint and possibly the cost. NO DISCLOSURES

Introduction: Occipito-cervical fusion has evolved from the used of simple onlay bone grafts to the use of sophisticated modular implants. Initial stiffness prevents micromotion and allows a higher fusion rate. Methods: A composite occipito-cervical model (OCM) was developed and validated using data obtained from cadaveric specimens. A jig was designed to pot the OCM, which allowed the application of independent moment forces to simulate flexion, extension, lateral flexion and rotation. The following implants were used 1 ) Grob plate with C1/C2 transarticular screw fixation.2) Grob Plate without C1/C2 transarticular screw fixation.3) Cervifix rod system 4) A Ransford loop system 5.) Olerud plate fixation. A three dimensional ultrasonic motion analysis system (Zebris Inc.) was used to record motion at three positions: 1)C0 2) C2 3) C4.A separate OCM was used for each instrumentation system. Results: The Grob plate with C1/C2 transarticular fixation was found to confer the greatest initial stiffness. The Ransford loop construct was found to confer the least initial stiffness. Plate fixation offered greater stability then rod or loop constructs. We found the three dimensional motion analysis system to be ideal for displacement analysis in complex spinal instrumentation constructs

The purpose of this study is the biomechanical comparison of five C1 – C2 posterior arthrodesis techniques. Ten adult human cadaveric upper cervical spine specimens were sectioned at the C3 level. The occiput and C3 vertebra were potted in PMMA. The specimens were tested intact; after destabilizing with odontoid transection and sectioning of the transverse and capsular ligaments; and after stabilization with Brooks-Jenkins cable fixation, Brooks-Jenkins with unilateral transarticular screw, Gallie posterior wire construct with unilateral transarticular screw, Brooks-Jenkins with bilateral screws, and Gallie with bilateral screws. Data were analysed with special attention paid to the motion at C1 – C2. The neutral zone (NZ) and range of motion (ROM) were measured in the main plane of each motion, as well as in coupled planes. In flexion / extension and lateral bending, the ROM and NZ increased significantly in the injured specimens as compared to the intact (p< 0.0001). In axial torsion, there was no significant difference between the intact and injured spines at C1 – C2 level. In the different fixation systems, the ROM and NZ were significantly lower than in injured and intact spines in all motions (p< 0.01), except the lateral bending in intact spine. Among the 5 instrumentations, the NZ and ROM in flexion / extension for the Gallie construct with one screw were significantly higher than for the Brooks-Jenkins construct with one or two screws (p< 0.05). In axial torsion, the Gallie construct with one screw displayed a larger NZ and ROM than any of the other four constructs (p< 0.05)

To define how pre-operative evaluation guides surgical planning in patients with atlanto-axial subluxation secondary to rheumatoid arthritis and to measure clinical outcome for the same group. Prospective evaluation of a consecutive cohort of 26 patients undergoing C1/2 fusion over 5 years (2004-2009). Pre-operative evaluation of posterior atlanto-dens interval (PADI), C1 lateral mass and C2 pedicle dimensions. Pre- and post-op Ranawat scores and visual analogue scores for neck and C2 pain. C1/2 instability resulted from rheumatoid arthritis (21), trauma (4) and infection (1). C1 lateral mass mean height 4.4mm, C2 pedicle mean height 5.1mm and mean width 3.4mm (30% width <3mm). Ranawat scale improved Grade II to Grade I (p=0.07). Neck pain (pre-op mean 5.5, s.d. 2.8; post-op mean 1.6, s.d. 2.1, t<0.05) and C2 pain (pre-op mean 2.1, s.d. 3.3; post-op mean 0.5, s.d. 1.2, t<0.05) improved. No instrumentation failure. In the rheumatoid group, 17/21 patients had C1 lateral mass and C1/2 transarticular screws. 1 patient had a cranio-cervical fusion and 3 patients had other constructs. 3 patients had C2 numbness. No other neurological deficit. In a rheumatoid population, pre-operative evaluation often precludes the use of C2 pedicle screws. Rigid fixation with a C1 lateral mass and C1/2 transarticular polyaxial screw-rod system is associated with good clinical outcomes

Goals: Advantage of the dorsal fixation of C1/2. Materials and Methods: From 01/2006 to 12/2006 22 patients with a traumatic fracture of C1/2 were operativly stabilized. The avarage age was 79 year (66–92). No neurological deficit. Diagnostic was always a CT-scan for classification of fracture typ. 7 patients were temporarily immobilized with HALO fixateur. Within th next 8 days final operation hab been carried out. 7 patients with Anderson fractures typ II were stabilized with open fixation from ventral (group 1). 4 Jefferson fractures and 2 combined C1/2 fractures were were stabilized with open fixation from dorsal (Magerl) (group 2). Percutanous fixation from dorsal was done in 5 patients with fractures of the atlas, 4 with Anderson fractures typ II (group3). Clinical and radiological follow up was done in 18 patients. Results: Duration for operation was in 64min in group1, 134min in group 2 and in 42min in group3. No neurological deficit or damage of A.vertebralis occurred. Blood loss was in group 1 and 3 under 50ml in group 2 750ml. In group3 one slightly dislocation of screw happened without need of revision. Movement of cervical spine was reduced in group 2 and 3. During follow up 3 of seven ventral stabilized Anderson fractures typ II (group1) were dislocated. Dorsal percutanous fixation for operatively revision was done. Discussion: Percutanous dorsal transarticular screw fixation C1/2 is a challanging procedure for stabilization of atlantoaxial fractures. Main advantages compared to other operation techniques are less blood loss, short operation time, high rate of success

Introduction: The management atlanto-axial fractures, particularly those of the odontoid peg, remains controversial. We managed patients with C1/C2 fractures non-operatively in rigid immobilization until CT-scanning confirmed bony union, rather than for the standard 3-month period. We examined whether this improved outcomes and reduced the need for surgery. Method: All patients admitted to our unit with atlanto-axial fractures between 2001–2007 were retrospectively analyzed. All fractures had the ‘intention-to-treat’ conservatively in either halothoracic vest (85%) or Aspen collar (15%). Rigid immobilization was maintained until CT-scanning demonstrated bony fusion. Functional stability was subsequently assessed with flexion-extension radiographs after removal of rigid immobilization. Results: Twenty-seven patients were studied. Nineteen had odontoid peg fractures (10 type II; 9 type III). The remainder consisted of 3 Hangman’s, 3 lateral mass and 2 atlas ring fractures. 83% of patients progressed to union at an average of 13.2 weeks (range 5–22). Six complications related to halo immobilization were observed (three skull perforations/pin-site infections). All of these patients progressed to union non-operatively. Failure of non-operative management was deemed as non-union or poor patient tolerance of halo, and occurred in 4 patients (17%). All four had type II odontoid peg fractures, and had transarticular screw fixation. One postoperative complication of screw fracture was recorded. Conclusion: Non-union rates of conservatively managed atlanto-axial fractures with standard 3-month rigid immobilization have been reported as high as 35%. In our series, CT-imaging to confirm bony union prior to removal of the rigid immobilization (prolonging immobilization where necessary) significantly lowered the rate of non-union and therefore the need for subsequent surgery. Ethics approval: None Audit. Interest Statement: None

Introduction: TMTJ fusion is performed for arthritis or painful deformity. First TMTJ fusion may be performed for Hallux valgus deformity. K-wire and trans-articular screws are usually used to stabilize the joints. We present our audit of experience with LP for TMTJ fusion. Patients and Methods: 33 TMTJ in 19 patients were fused and stabilised using LP between January and September 2008. The procedure was performed for Lisfranc arthritis in 13 and Lapidus procedure in 6. Two out of 6 were revisions after failed fusion using transarticular screws. Iliac crest bone autograft was used in 26 joints in 12 patients. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone union. AOFAS mid-foot scale was also used as an outcome measure. Results: There were 7 male and 12 female patients with average age of 51 (14–68). AOFAS midfoot scale showed 42% improvement in pain, 30% improvement in function and 53% improvement in alignment. Average total AOFAS score improved from 30 preoperative to 67 postoperative. All except 1 joint in one patient had clinical and radiological fusion of their joints. 1 patient needed removal of metalwork and 4 had delayed wound healing. Average satisfaction score was 7/10. 86% Patients would recommend it to a friend and 91% would have it again. Discussion: Locking plates have been recently introduced for ankle and foot surgery. Biomechanical studies have shown plates are not as strong or stiff as trans-articular screw fixation however they are easy to use, have more flexibility for realignment and can act as a buttress for bone graft. In our review all patients except one had bone union without loss of alignment. Conclusion: TMTJ fusion improves pain and function. Locking plates provide satisfactory stability for TMTJ fusion

Introduction: Tarsometatarsal joint (TMTJ) fusion is performed for arthritis or painful deformity. First TMTJ fusion may be performed as a part of corrective surgery for hallux valgus deformity. K-wires and trans-articular screws are often used to stabilize the joints. We present our experience with the use of locking plates (LP) for TMTJ fusion. Patients and Methods: Thirty-three TMTJ’s in 19 patients were fused and stabilised with LP’s between January and September 2008. The procedure was performed for Lisfranc arthritis in 13 patients and Lapidus procedures in six. Two out of 6 were revisions after failed fusion using transarticular screws. Iliac crest bone autograft was used in 26 joints in 12 patients. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone union. AOFAS midfoot scale was used as outcome measure. Results: There were 7 male and 12 female patients with average age of 51 (14–68). The American orthopaedic foot and ankle surgery society (AOFAS) midfoot score showed a 42% improvement in pain, 30% improvement in function and 53% improvement in alignment. The average AOFAS overall score improved from 30 preoperativley to 67 postoperativley. All except one joint in one patient had clinically and radiologically fused joints. One patient underwent removal of the metalwork and four had delayed wound healing. The average satisfaction score was 7 out of 10. 86% said of patients said that they would recommend the surgery to a friend, and 91% would undergo the surgery again. Discussion: Locking plates have been recently introduced for ankle and foot surgery. Biomechanical studies have shown that the plates are not as strong or stiff as trans-articular screw fixation, however, they are easy to use, have more flexibility for realignment and can act as a buttress for bone graft. In our series all, except one, patients achieved bony union without loss of alignment. Conclusion: Locking plates provide satisfactory stability for TMTJ fusion, without complications

Pedicle screws give the best bone purchase of all posterior fixation techniques of the cervical spine, which would suggest a frequent utilisation. However, the cervical pedicles are small and the potential danger of misplacing a screw limits their use. In in vitrostudies the misplacement frequency has been shown to be unacceptably high, whereas this is not seen clinically, maybe due to different insertion techniques. Fortunately a misplaced screw rarely leads to a clinical complication. To minimise the risks, however, we now only use pedicle screws in the cervical spine where stability is critical, i.e. at the extremes of a fixation. For example: A C1–C2 fixation in rheumatoid arthritis or in fracture of the dens would utilise C2–C1 transarticular screws (i.e. C2 pedicle screws). A cranio-cervical or cranio-thoracic fixation would involve 1 or 2 levels of pedicle screws as distal anchorage, and lateral mass screws in between. A short cervical fixation with pedicle screws could be in a trauma patient where it would be desired to have a very reliable fixation with a minimum number of fixation levels. Computer navigation is a promising technique, however, not free from misplaced screws. So far we have experience of 83 navigated screws in 18 patients evaluated with postoperative computed tomography (CT). 67 screws were in correct position, 11 had insignificant breach fractures of the pedicle wall, whereas 4 were incorrectly placed, usually laterally into the foramen for the vertebral artery, none however with a clinical consequence. The main problem with computer navigation in the c-spine seems to be to obtain a good enough CT scan to allow good matching between the virtual and real worlds

Introduction: The management of cervical spine fracture, subluxation or dislocation in the elderly may present difficulties in decision-making. Frequently, the elderly suffer from medical comorbidity and a limited physiological reserve, which need to be considered in deciding on surgical versus conservative management of fractures and dislocations. Debate exists regarding the merits of surgical versus nonsurgical management of these injuries. 1,. 2,. 4. Methods: Retrospective analysis of 16 patients with traumatic cervical spine fractures with or without dislocation or subluxation in patients greater than 65 years of age, spanning 1994 to the present were carried out. Success of spine stabilisation, time in hospital, ability to return to pre-injury function and medical or surgical complications were measured. Results: The average age of the patients was 76 years with a range of 67–86 years of age. A variety of cervical injuries and fixation methods were identified, the most common injury being odontoid fracture requiring transarticular screw fixation. One patient died eight days post-operatively of cardiac arrest and a second patient died of pneumonia. One other complication of wound hematoma while the patient was taking anticoagulation therapy occurred. All other patients were discharged independent in activities of daily living. There were no cases of failure of surgery to restore stability. No post-operative neurological deterioration in any of the patients occurred. Discussion: This study shows that surgical fixation of cervical fractures in the elderly can be performed as a safe and efficient form of management. Surgery decreases the period of both immobility and hospitalisation with subsequent decrease in the risk of complications such as deep vein thrombosis, pulmonary embolism and pneumonia. 3. Complications from immobilisation devices such as the halo-thoracic brace may also be avoided

Purpose: Cage fusion of the L5–S1 segment is a controversial issue due to the weak stabilisation of the spine during extension and axial rotation. Complementary fixation appears to be needed to improve stability, but the presence of the bifurcation of the great vessels is an anatomic limitation. We studied the anatomy of this area to examine the feasibility of anterior plate fixation. Material and methods: According to the recognised anatomic references (Rouvière, Bouchet and Cuilleret, Louis), a 33-mm safety zone was described at the aortoiliac and iliocaval bifurcation. This space free from contact with the greater vessels lies in front of the L5–S1 disc. Pre-operative angio-MRI was used to assess the size of this safety zone. A triangular anterior plate was designed for arthrodesis (Pyramid Sofamor Danek, USA). An L5–S1 arthrodesis was performed in 15 consecutive patients using this plate. Follow-up was one year. A video-assisted anterior retroperitoneal approach was used in all cases. The Prolo and Oswestry scores were used for the preoperative and last follow-up evaluations. Results: According to the anatomic study and the MRI views, 89% of the patients had a sufficient safety zone for plate fixation. The method was contraindicated in two patients who had a low bifurcation. Angio-MRI was found to be simple and reproducible. The MRI analysis was confirmed at surgery (no false negatives). The plate was successfully implanted in 15 patients with no contact with the great vessels. There were no serious complications (vascular, neurological, urological, digestive). The economic Prolo score was improved from 2.7 to 4.2 and the functional score from 2.6 to 4.3. The Oswestry score improved 33%. The rate of clinical success was 93% (14/15 patients). Discussion and conclusion: Implantation of an anterior plate for L5-S1 fusion is feasible. The key points are: 1) rigorous preoperative evaluation of the greater vessel bifurcation; 2) anatomic plate design; 3) appropriate surgical technique. The risk of retrograde ejaculation is related to retraction of the hypogastric plexus and should be investigated with a prospective study. This osteosynthesis technique can avoid secondary operations for fixation with pedicular or transarticular screwing

Introduction: Fixation of the atlantoaxial complex has traditionally involved transarticular screws combined with posterior wiring techniques and structural bone grafting. Although this does lead to excellent fusion rates, the technique has a potential risk of injury to the vertebral artery. In addition, it cannot be used in fixed subluxation of the C1/2 complex. We describe the use of C1 lateral mass screws in combination with C2 pedicle screws for safe and versatile C1/C2 fixation. Methods: Over a fifteen month period, (July 2003–October 2004) a total of 10 patients underwent posterior C1/ C2 fixation alone, or as part of a more extensive posterior construct. The average age was 54.25 years, ranging from 20–78 years. There were 7 women and 3 men. The average length of stay was 18.5 days ranging from 5–36 days. Technique: A midline posterior approach was used in all cases. The C2 roots were mobilized and the C1 lateral masses identified bilaterally. A drill was inserted into the middle of each lateral mass under image intensification. Bicortical polyaxial screws were then inserted. The C2 pedicle screws were inserted under direct vision, as were the other pedicle screws in the more extensive constructs. Contoured rods and posterior iliac bone graft were used in all cases. Results: Five patients required isolated C1/C2 fusion for instability, two patients had an odontoid fracture non-union, one had an unstable C2 fracture, and the remaining two patients had C1/C2 subluxation secondary to rheumatoid arthritis. More extensive posterior instrumentation was performed for the following cases, these included; occipitothoracic fixation in one patient with rheumatoid arthritis with multi-level cervical subluxation, and occipitocervical fixation in three patients, two who had metastatic disease in the cervical spine, and the remaining patient who had rheumatoid arthritis. The final patient was instrumented from C1–C5 posteriorally following removal of a C3 giant cell tumour. No neurological or vascular complications were observed. One patient, with rheumatoid arthritis and osteoporosis, had a halo applied to protect an occipitothoracic construct. All other patients were discharged in a Miami-J cervical collar. The early follow up data, clinical and radiological, showed fusion in all patients. There were no implant failures. Conclusion: The combination of C1 lateral mass and C2 pedicle screws allows safe, effective and versatile fixation of the C1/C2 complex