Posterior C1-C2 Fusion Research Articles

Occipitocervical or C1-C2 fusion using allograft bone in pediatric patients with Down syndrome 8 years of age or younger.

Sufficient internal fixation for occipitocervical (OC) or C1-C2 instability in pediatric patients with Down syndrome is difficult owing to small osseous structures, congenital deformities, and immature ossification. The purpose of this study was to evaluate the clinical outcomes of patients aged 8 years or younger with Down syndrome who underwent OC or C1-C2 fusion using freeze-dried allograft as bone graft substitute. The participants included seven consecutive patients aged 8 years or younger with Down syndrome who were treated for upper cervical disorders with posterior OC or C1-C2 fusion using freeze-dried allografts at our hospital between 2007 and 2016 and had a minimum follow-up of 1 year. Postoperative flexion/extension cervical radiography and computed tomography were repeated at 3 months after surgery before removal of the collar. The modified McCormick scale was used to grade functional status. The seven patients had an age range of 5-8 years (mean: 5.9 years). The mean follow-up period was 36 months (12-120 months). Six patients had os odontoideum and one had basilar invagination. Three patients underwent C1-C2 fusion, and in all cases, bilateral C1 lateral mass screws and bilateral C2 pedicle screws were used. Four patients underwent OC fusion, and in three of these cases, occipital and bilateral pedicle screws were used. One patient underwent reoperation because of occipital screw back-out with autograft; therefore, C2 lamina screws were added to pedicle screws. Solid bony fusion was achieved, and stable constructs were maintained on radiography in all patients, without infection or implant failure. In this study, we used freeze-dried allograft as a bone graft substitute, and we were able to detect bony trabeculae at the graft-recipient interface on lateral cervical radiographs and on reconstructed sagittal computed tomographic images in all patients. These results suggest that use of allograft is effective for treatment of upper cervical spine abnormalities in pediatric patients with Down syndrome.

Mortality Rates After Posterior C1-2 Fusion for Displaced Type II Odontoid Fractures in Octogenarians.

Retrospective cohort study OBJECTIVE.: To assess 30-day and 1-year mortality rates as well as the most common complications associated with posterior C1-2 fusion in an octogenarian cohort. Treatment of unstable type II odontoid fractures in elderly patients can present challenges. Recent evidence indicates in patients older than 80 years, posterior C1-2 fusion results in improved survival as compared to other modes of treatment. Retrospective analysis of 43 consecutive patients (25 female and 18 male; mean age 84.3 yr, range 80-89 yr; mean Charlson Comorbidity Index 1.4, (range 1-6); mean body mass index 24.8 ± 4.2 kg/m, who underwent posterior C1-C2 fusion for management of unstable type II odontoid fracture by four fellowship trained spine surgeons at a single institution between January 2006 to June 2016. Mean fracture displacement was 5.1 ± 3.6 mm and mean absolute value of angulation was 19.93° ± 12.93°. The most common complications were altered mental status (41.9%, n = 18), dysphagia (27.9%, n = 12) with 50% of those patients (6/12) requiring a feeding tube, and emergency reintubation (9.3%, n = 4). To the date of review completion, 25 of 43 patients expired (58.1%), median survival of 1.76 years from the date of surgery. Thirty-day and 1-year mortality rates were 2.3% and 18.6%, respectively. Patients who developed dysphagia were 14.5 times more likely to have expired at 1 year; dysphagia was also found to be significantly associated with degree of displacement. Fracture displacement was found to be associated with increased odds for 1-year mortality when accounting for age and requirement of a feeding tube. Posterior C1-2 fusion results in acceptably low mortality rates in octogenarians with unstable type II odontoid fractures when compared to nonoperative management mortality rates in current literature. Initial fracture displacement is associated with higher mortality rate in this patient population. 4.

C1–C2 Fusion Versus Occipito-Cervical Fusion for High Cervical Fractures: A Multi-Institutional Database Analysis and Review of the Literature

Type II odontoid fractures of the axis (C2) account for more than 20% of all cervical fractures. If an odontoid screw is contraindicated, the treatment approach for type II C2 fractures typically involves C1-C2 posterior fusion or occipito-cervical (O-C) fusion, each of which has distinct advantages and disadvantages. In this study, postoperative outcomes of C1-C2 fusion and O-C fusion for high cervical fractures were compared. The American College of Surgeons National Surgical Quality Improvement Program database was queried to determine 30-day surgical outcomes of posterior C1-C2 fusion versus O-C fusion for adult patients with C2 fractures between 2005 and 2016. Demographics, operative factors, and postoperative events were analyzed, including returns to the operating room, readmission, and death. In total, 165 patients were identified. A majority of the patients (142, 86.1%) had independent functional status, although 133 (80.6%) had an American Society of Anesthesiologists classification ranging from 3 to 5, representing poor preoperative health. A significantly greater proportion of O-C (9.1%) versus C1-C2 fusion (1.7%) returned to the operating room (odds ratio 6.465, confidence interval 1.079-38.719, P= 0.041). The length of operation approached statistical significance (P= 0.053) between the 2 groups, with O-C fusion group having a longer average length of operation (196.4 minutes) versus the C1-C2 group (164.0 minutes). This study provides a snapshot of the risk profiles of C1-C2 and O-C fusion for C2 fracture, demonstrating a statistically higher risk of reoperation in O-C fusion versus C1-C2 fusion. Future randomized trials are needed to identify the preferred technique to improve patient outcomes.

Value of neurophysiologic monitoring in confirming indirect decompression of severe pediatric non-traumatic C1–C2 subluxation. A case report

Abstract Spinal cord compression from severe C1–C2 subluxation is a complex and challenging neurosurgical problem. A combination of surgical approaches may be required to decompress the spinal cord, including anterior transoral odontoidectomy, posterior cervical laminectomy, or indirect decompression by subluxation reduction. After decompression, an instrumented posterior fusion is then required to stabilize the spine. We report a case of a 13-year-old-girl who presented with spastic quadriparesis secondary to severe atlantoaxial subluxation, where intraoperative neurophysiologic monitoring (IOM) guided surgical decision making. The patient had congenital osseous abnormalities, including incomplete segmentation of C2 on C3, predisposing her to atlantoaxial dislocation. She underwent open surgical reduction of the C1–C2 subluxation with multi-modal intraoperative neurophysiologic guidance. Translaminar C2 screws and C1 lateral mass screws were placed bilaterally. Using a previously described distraction technique, we performed ventral translation of C2 relative to C1, thereby reducing the subluxation. Intraoperative radiographic images and neurophysiologic monitoring revealed significant improvements, confirming that adequate indirect decompression had been achieved. After subluxation reduction with intraoperative monitoring (IOM) improvements, we decided to proceed with a C1–C2 posterior fusion and avoid a cervical laminectomy and more extensive occipital cervical fusion procedure. After one year, the girl made a complete neurologic recovery and remains symptom-free 3 years post-surgery. Fusion to the occiput would have potentially caused greater morbidity in this patient. The neurophysiologic monitoring confirmed indirect decompression and served as a critical tool for the prediction of favorable neurologic outcome.

C2 dens fracture with closed cervical migration of a 6cm humeral fragment

Case: A 39-year-old woman, with bipolar disorder, suffered an eight-meter fall, resulting in dens and proximal and distal humeral fractures associated with migration of a 6cm humerus fragment to the left cervical region. There were no skin breaches on admission. Posterior instrumented C1-C2 fusion was performed along with proximal humerus stabilization through anterograde static nailing after removal and repositioning of the cervical migrated fragment. Conclusion: High-energy trauma significantly increases treatment complexity. Understanding injury mechanism is crucial to adequately diagnose undisclosed lesions that otherwise might go unnoticed. In cases of bone migration, a thorough debridement is advised to prevent heterotopic calcifications.

Use of intraoperative X-ray to differentiate between reducible versus irreducible atlantoaxial dislocation.

Background:The treatment and classification of atlantoaxial dislocations (AADs) remain controversial. Here, we utilized intraoperative X-ray to differentiate between reducible and irreducible AADs.Methods:Five patients were diagnosed as having irreducible AAD on dynamic and post-traction X-rays. Under general anesthesia, they were placed prone in a neutral position utilizing skeletal traction. The X-rays and motor evoked potential (MEP), were then monitored before, during, and after placing a thumb on the C2 spinous process and pushing it anteriorly to attain reduction.Results:The intraoperative X-ray confirmed reducibility of AAD in four patients; they subsequently underwent a C1–C2 posterior fusion, which maintained that reduction. For the one patient with an irreducible AAD (despite thumb maneuver), an anterior release was required first to attain reduction, followed by posterior C1–C2 fusion.Conclusion:Here, we divided irreducible AAD into two categories: a) reducible—utilizing a thumb maneuver to compress/push the C2 spinous process forward with the patient positioned prone and b) irreducible—those who cannot be reduced with this technique. A posterior only approach was sufficient for those with “reducible” AAD, whereas those who could not be reduced required an anterior release followed by posterior fusion.

C1-C2 Pedicle Screw Fixation for Pediatric Atlantoaxial Dislocation: Initial Results and Long-term Follow-up.

There are few studies reporting the use of atlantoaxial pedicle screws and the long-term effects of C1-C2 posterior fusion in children. Our study is to investigate the initial results of C1-C2 pedicle screw fixation for pediatric atlantoaxial dislocation (AAD) and assessed spontaneous change of postoperative radiography after a long-term follow-up period. Posterior pedicle screw fixations were performed in 21 pediatric patients with AAD. All the patients underwent implant removal 1 year after their initial surgery and had regular follow-up with an average duration of 76.4 months (range, 52 to 117 mo). Clinical and radiographic data were then collected and compared. Frankel Grade was significantly improved at 3 months follow-up compared with pretreatment values. All patients had good bony fusion at a mean of 4.2±0.9 months (range, 3 to 6 mo) after treatment. None of the patients experienced worsening neurological symptoms or injury to the vertebral artery. However, 2 cases experienced minor complications. Following removal of the implants, no spinal deformities or subaxial instabilities were found. The mean angle of sagittal curvature increased from 12.1±2.4 degrees (range, 0 to 22 degrees) immediately postoperatively to 19.1±2.7 degrees (range, 6 to 31 degrees) at the final follow-up (P>0.05). The results demonstrated that C1-C2 pedicle screw fixation could achieve satisfactory initial results for the management of the pediatric AAD. Moreover, removal of the metal implant after bony fusion did not increase the risk of spinal deformity or subaxial instability at long-term follow-up.

Posterior C1-C2 screw-rod fixation and autograft fusion for the treatment of os odontoideum with C1-C2 instability

ObjectiveTo report our experience treating os odontoideum with C1-C2 instability via C1-C2 screw-rod fixation and autograft fusion and to explore the clinical efficacy of such a treatment strategy. Patients and methodsWe retrospectively reviewed the medical records of patients who were diagnosed with os odontoideum with C1-C2 instability and treated by posterior C1-C2 screw-rod fixation and fusion. Neurological deficits were measured with the Japanese Orthopedic Association (JOA) scoring system and neck pain was assessed using the Visual Analogue Scale (VAS) score. Fusion was determined based on the presence of bridging bone in computed tomography (CT) imaging, whereas stability was determined based on the lack of movement in dynamic radiographs. ResultsThirty-two patients (18 males) were included in the study. The surgery was successfully accomplished in all patients. Thirty (93.8%) patients had confirmed C1-C2 bony fusion in CT images and all patients (100%) were stable in dynamic radiographs. The mean preoperative JOA score was 14.3±1.4 (range 11–16); at the final visit, it increased to 16.2±0.8 (range 14–17) (p<0.001). The mean preoperative VAS score was 3.8±0.7 (range 3–5) and decreased at the final visit to 1.0±0.6 (range 0–2) (p<0.001). ConclusionOur treatment strategy (C1-C2 screw-rod fixation and autograft fusion) can achieve excellent clinical results with minor complications for patients with os odontoideum with C1-C2 instability.

Surgical overreduction and hyperlordotic fusion of C1-C2 joint are associated with cervical sagittal malalignment.

Previous studies have shown that hyperlordotic C1-C2 fusion was related to postoperative subaxial kyphosis. However, most of the patients in these studies were complicated with rheumatoid arthritis (RA). Moreover, no studies have specifically evaluated the relationship between C1-C2 fusion angle and cervical sagittal vertical axis (cSVA), T1 slope or cranial tilt (CRT) after posterior C1-C2 fusion. This study aimed to investigate the cervical sagittal alignment in non-RA patients following posterior C1-C2 fusion and the correlation between C1-C2 fusion angle and postoperative cervical sagittal alignment. From August 2004 to December 2015, twenty-eight consecutive patients with an average age of 39.2years (range 6-70years) who underwent posterior C1-C2 fusion from a single institution were enrolled. The mean follow-up period was 30.7months (range 12-77months). Angles of Oc-C1, C1-C2, C2-C3 and C2-C7, cSVA, T1 slope and CRT were measured in lateral cervical radiographs in neutral position before surgery and at the final follow-up. C1-C2 angle significantly increased from 13.6°±12.4° to 22.0°±8.1° at the final follow-up (P<0.001). A significant decrease was found both in Oc-C1 and C2-C7 angles from pre-operation to the final follow-up (P<0.001 and P=0.011, respectively). Moreover, cSVA and CRT dramatically increased from pre-operation to the final follow-up (P<0.001). C1-C2 fusion angle was significantly associated with Oc-C1, C2-C7 angle, cSVA and CRT at the final follow-up. A significant correlation was also observed between postoperative change of C1-C2 angle and that of Oc-C1, C2-C7 angle, cSVA and CRT. Apart from decreased subaxial lordosis, posterior C1-C2 fusion in hyperextension may also lead to kyphotic change of atlanto-occipital alignment and increased tilting forward of the cervical spine. Therefore, intraoperative overreduction of C1-C2 angle and hyperlordotic C1-C2 fusion should be avoided to maintain the physiologic cervical sagittal alignment.

C2 and Greater Occipital Nerve: The Anatomic and Functional Implications in Spinal Surgery.

IntroductionPosterior C1-C2 fusion is a highly successful treatment for atlantoaxial instability and other pathologies of the cervical spine, with fusion rates approaching 95%-100%. However, poor visualization of the lateral masses of C1 secondary to the course of the C2 nerve root along with blood loss from the venous plexus and compression of the C2 nerve from lateral mass screws are technical obstacles that can arise during surgery. Thus, sacrifice of the C2 nerve root has long since been debated in fusions involving the C1 and C2 vertebral bodies. MethodsCadaveric dissections on four adult specimens were performed. Both intradural and extradural courses of C2 were studied in detail. The tentative site of C2 nerve root compression during placement of C1 lateral mass screws was studied in detail. Both the indication as well as the ease of C2 neurectomy were studied in relation to postoperative compression and entrapment.ResultsFour-six dorsal rootlets of C2 nerve were observed while studying the intradural course. The extradural course was studied with respect to the lateral mass of C1. The greater occipital nerve (GON) course was fairly consistent in all specimens. Transection of C2 around its ganglion would allow for proper C1 lateral mass screw placement as the course of C2 nerve interferes with proper placement of instrumentation.ConclusionC2 nerve root transection is associated with occipital numbness but this often has no effect on health-related quality of life (HRQOL). The C2 nerve root preservation is often associated with entrapment neuropathy or occipital neuralgia, which greatly affects HRQOL. The C2 nerve root transection helps in better visualization, aids in optimal placement of C1 lateral mass screws, minimizes estimated blood loss and improves surgical outcome with successful fusion.

Comparison of outcomes after atlantoaxial fusion with C1 lateral mass-C2 pedicle screws and C1-C2 transarticular screws.

To compare the clinical and radiological outcomes of posterior atlantoaxial fixation and fusion using C1 lateral mass-C2 pedicle screws (screw-rod constructs, SRC) with C1-C2 transarticular screws (TAS). A retrospective review was conducted of 105 patients with atlantoaxial instability who underwent posterior C1-C2 fixation and fusion by SRC group (60 pt) and TAS group (45 pt). The follow-up period was minimum 2years. Clinical outcomes measurements included the Numeric Rating Scale (NRS) for pain assessment, the Neck Disability Index (NDI), the Japanese Orthopedic Association (JOA) score and the American Spinal Injury Association (ASIA) impairment scale for the functional and neurological outcomes that were assessed. Radiological outcomes were assessed by evaluating the fusion rate and proper screws position. Both outcomes were evaluated in the early postoperative period, 3, 6, 12 and 24months after surgery. Operative time, estimated blood loss, complications and length of stay were also reviewed. The majority of cases were caused by trauma and presented with axial neck pain. The improvement of NRS, NDI, JOA score and ASIA impairment scale were not different between the two groups. Proper screw position and fusion rate were also observed similarly between the two groups. Estimated blood loss was lesser and operative time was shorter in TAS group than SRC group (p=0.047, p=0.001, respectively). Operative complications and the length of hospital stay were also not different between the two groups. Both SRC and TAS produced excellent outcomes for atlantoaxial stabilization. But the volume of bleeding and operation time tended to be better in TAS group compared to SRC group.

Influence of the T1-slope on sagittal alignment of the subaxial cervical spine after posterior atlantoaxial fusion in os odontoideum

ObjectivesTo analyze the effect of T1-slope (T1S) on sagittal alignment of the subaxial cervical spine after posterior C1-C2 fusion. Patients and methodsThe data of 35 consecutive patients who underwent posterior C1-C2 fusion due to atlantoaxial instability with os odontoideum were retrospectively reviewed. Radiographic parameters, including T1S, C1-C2 angle and C2-C7 angle, were measured before operation and at the final follow-up. Patients were divided into 2 groups: high T1S group and low T1S group. Differences within and between groups in radiographic parameters and the relationships among T1S, C1-C2 angle and C2-C7 angle were analyzed. ResultsAfter operation, C1-C2 angle was significantly enlarged (P<0.05) while C2-C7 angle reduced (P<0.05). However, significant change was not observed in T1S (P>0.05). Postoperative C2-C7 angle had a medium positive relation with both preoperative (r=0.563, P<0.05) and postoperative T1S (r=0.547, P<0.05). C1-C2 angle was negatively related to C2-C7 angle before operation (r=−0.590, P<0.05) but not after operation (r=−0.125, P>0.05). However, change of C1-C2 angle demonstrated a medium negative relation with change of C2-C7 angle after operation (r=−0.614, P<0.05). When the patients were divided into high and low T1S groups, there were significant difference in both preoperative and postoperative C2-C7 angles between 2 groups (all P<0.05) but not in C1-C2 angle, change of C1-C2 angle or change of C2-C7 angle (all P>0.05). After operation, C1-C2 angles became larger in both groups (all P<0.05). Meanwhile, although postoperative C2-C7 angle became smaller than preoperative one in both groups, statistical difference was only observed in high T1S group (P<0.05). ConclusionT1S was a useful parameter to evaluate postoperative alignment of the subaxial cervical spine after posterior C1-C2 fusion. To avoid postoperative misalignment of the subaxial cervical spine, C1-C2 should be fixed in less lordosis, especially in patients with high preoperative T1S.

Successful Treatment of Severe Occipitocervical Pain from C1-C2 Osteoarthritis Using a Modified Harms Technique

Introduction C1-C2 fusion with instrumentation is an established treatment for C1-C2 instability due to trauma or inflammatory disease. C1-C2 fusion for debilitating occipitocervical pain secondary to C1-C2 osteoarthritis has been reported in a small number of patients. Here we report the successful treatment of three patients that underwent C1-C2 instrumented fusion using a modified Harm's technique for medically refractory occipitocervical pain. Materials and Methods Between August 2012 and July 2015, three consecutive patients with debilitating, unilateral occipitocervical pain and radiographic C1–2 osteoarthritis, underwent posterior instrumented C1-C2 arthrodesis using bilateral polyaxial C1 lateral mass and C2 pedicle screw and rod constructs (modified Harms technique). All three patients failed preoperative conservative treatment including therapy, medical management and interventional pain management including facet joint injections. In all three patients, the source of occipitocervical pain was confirmed preoperatively with direct C1-C2 joint injection using 0.5ml of a mixture of 2% lidocaine/0.5% Marcaine/10mg kenalog. All three patients had immediate but temporary relief of their occipitocervical pain from the diagnostic C1-C2 joint injection. Preoperative CT scan confirmed the presence of C1-C2 osteoarthritis on the symptomatic side. Outcome measures include pre and postoperative VAS, patient reported resolution of pain, hospital LOS, EBL and complications. Results Each of the three patients surgically treated had complete resolution (100%) of their preoperative occipitocervical pain beginning immediately after instrumented posterior fusion of C1–2. Average VAS improved from 8.3 preoperatively to 0.0 postoperative for the cohort. Average follow up is 33 months. Average age for the group at the time of surgery was 75 years old and the M:F ratio is 1:2. Hospital LOS was 1 day for each patient. EBL was 45ml on average with a range of 15ml - 75ml. There were no postoperative complications. Conclusions Instrumented posterior C1-C2 fusion, using a modified Harms technique, is a safe and effective treatment for refractory occipitocervical pain secondary to C1-C2 osteoarthritis. The source of pain should be confirmed preoperatively with both CT scan and diagnostic joint injection.

Respiratory Arrest in a Patient with severe Cervical Dystrophic Kyphosis Secondary to Neurofibromatosis Type 1: A Case Report

Background: Cases of severe cervical kyphosis due to neurofibromatosis type 1 (NF1) and requiring tracheal intubation are rare. Dystrophic-type NF1 needs a combination of anterior and posterior spinal fusion, and use of sublaminar tape with rods appears reasonable and safe for posterior corrective spinal surgery in patients with this pathology. Case presentation: A 61-year-old woman with severe cervical kyphosis of 139 presented with sudden respiratory arrest before planned spinal surgery. Two-stage posterior and anterior corrective instrumented fusion using multiple segmental sublaminar tape and rods was performed under spinal cord monitoring. Cervical kyphosis was corrected from 104° to 83° and upper thoracic lordosis was corrected from 70° to 37°. Finally, she underwent additional posterior C1-C2 fusion with transarticular screwing for postoperative atlantoaxial subluxation. Solid bone fusion was demonstrated on 2-year follow-up Computed tomography, correction was maintained for 4 years after first surgery, and respiratory function was improved. Conclusion: Rib cage hypoplasia with upper thoracic lordosis secondary to severe cervical kyphosis can lead to acute-on-chronic respiratory failure. Planned corrective posterior spinal fusion with sublaminar tape, followed by anterior spinal fusion with a fibular strut bone resulted in successful solid bone fusion and improvement of respiratory function.

Erosion in the occipital bone caused by the fixation instrument used for posterior atlantoaxial fusion -report of 4 cases.

IntroductionConventionally, posterior C1-C2 fusion has been performed using a sublaminar wiring technique with a structural bone graft. Subsequent advent of newer fixation devices, such as the C1 lateral mass screw and C1 hook, has achieved more solid fixation with improved surgical outcome; however, in these fixation systems, the protruding end of the metal implant above the level of the atlas may result in a complication due to contact with the surrounding structures.Case descriptionTwo men and two women whose ages at the time of surgery ranged from 14 to 72 years. A supralaminar hook was used as a fixation device for C1 in two cases, whereas a lateral mass screw (Tan’s method) and an atlas claw hook were employed for one each of the remaining 2 cases. We retrospectively reviewed the clinical features and postoperative course of these patients using the clinical records. Moreover, we measured the protruding height of the instrument above the atlas as well as the Redlund-Johnell (R-J) value on postoperative radiographs. All patients complained of crepitus and/or pain on neck extension. Erosion in the occipital bone was detected on multiplanar reconstruction computed tomography (MPR-CT), whereas plain radiographs failed to reveal the bony change. In those cases, protruding instruments used for C1 fixation contacted the occipital bone resulting in an erosive change at the impingement point. We removed the implant in all four cases after confirmation of solid bony union.Discussion and evaluationTwo of the four patients complained of occipital crepitus alone without pain. The management options for this condition may be controversial; however, progression of bony erosion may result in perforation of the occipital bone. This may possibly be associated with the serious complication of cerebrospinal fluid leakage. Considering this potential sequela, we removed the implants from all our reported cases after confirmation of solid bony union.ConclusionsWe treated four cases that developed erosion in the occipital bone after posterior spinal instrumentation was performed for upper cervical lesions including C1. MPR-CT was useful in detecting the erosive changes in the occipital bone.

Myoarchitectonic advancement of the C2 spinous process for C1-C2 posterior fusion: A novel technique.

Study Design:Retrospective descriptive study of an innovative surgical technique.Objective:To assess the feasibility of using a large C2 spinous process as a vascularized bone graft donor with muscles attached to it in C1-C2 posterior fusion with evaluation of post operative fusion and pain in these cases.Summary of Background Data:C1-C2 posterior fusion essentially requires a bone graft and for this a separate incision is needed at the donor site with its associated morbidity. The procedure also entails detachment of muscles attached to the C2 spinous process. Due to the detachment of these muscles with important functions, postoperative nuchal pain is common in these patients. We developed a novel technique of harvesting the vascularized C2 spinous process as a bone graft to minimize the above-mentioned complications.Materials and Methods:Five patients with atlanto-axial dislocation due to various pathologies underwent C1-C2 posterior arthrodesis with the present technique. They were followed up for 6 to 18 months and were evaluated for feasibility of procedure, post operative fusion and post operative complications, especially pain.Results:The procedure was accomplished successfully in all patients without any perioperative complications. All patients were pain free 3 months after surgery—mean Visual Analogue Scale (VAS) was 0.4. Fusion (confirmed by plain radiography in three and by CT scan in two patients) was achieved in all five patients (100%).Conclusion:Myoarchitectonic advancement of C2 spinous process is a novel technique of C1-C2 posterior fusion in which a local vascularized bone graft is used avoiding donor site morbidity and at the same time preservation of dynamic function of muscles attached reduces the post operative pain.

Surgical Management of the Fractures of Axis Body: Indications and Surgical Strategy

Introduction The axis body fractures are relatively uncommon and have a variety of presentations. Surgical management to them has been only reported as case reports or included as a minor part of clinical management. The objective of this study is to summarize the indications for surgery and report the clinical outcome of surgical treatment based on different fracture patterns. Materials and Methods A retrospective analysis of 28 consecutive patients presenting with the axis body fractures was undertaken. The indications for surgical treatment were defined as follows: (1) fractures associated with instability of adjacent joints; (2) irreducible displaced superior articular facet fracture; (3) fractures resulting in spinal cord compression. The fractures were classified as sagittal, coronal, transverse and lateral mass fracture. One of the following surgical procedures was applied according to the fracture pattern: posterior C1-C2 pedicle screws fixation and fusion (I); posterior C1-C3 screws fixation and fusion (II); posterior osteosynthesis with C2 transpedicular half-thread lag screws (III). Results Thirteen patients were successfully managed operatively. Two transverse and two unilateral lateral mass fractures were treated with surgical procedure I, five sagittal fractures with II, four coronal fractures with III. Complications of malposition of screws and neurologic deficit did not occur during operation. Satisfactory reduction and bony union were demonstrated on postoperative radiographs. Conclusion The axis body fractures should be treated with individualized clinical management. Conservative remedies with external immobilization are still advocated as primary management for most cases. But for cases with adjacent joints instability or irreducible displaced superior articular facet fracture, surgical intervention is necessary. The optimal surgical choice should be based on the type of fracture pattern. Disclosure of Interest None declared References Starr JK, Eismont FJ. Atypical hangman's fractures. Spine 1993;18(14):1954–1957 Benzel EC, Hart BL, Ball PA, Baldwin NG, Orrison WW, Espinosa M. Fractures of the C-2 vertebral body. J Neurosurg 1994;81(2):206–212 Fujimura Y, Nishi Y, Kobayashi K. Classification and treatment of axis body fractures. J Orthop Trauma 1996;10(8):536–540 Korres DS, Papagelopoulos PJ, Mavrogenis AF, Benetos IS, Kyriazopoulos P, Psycharis I. Chance-type fractures of the axis. Spine 2005;30(17):E517-E520 German JW, Hart BL, Benzel EC. Nonoperative management of vertical C2 body fractures. Neurosurgery 2005;56(3):516-521, discussion 516–521 Koller H, Acosta F, Forstner R, et al. C2-fractures: part II. A morphometrical analysis of computerized atlantoaxial motion, anatomical alignment and related clinical outcomes. Eur Spine J 2009;18(8):1135–1153 Rainov NG, Heidecke V, Burkert W. Coronally oriented vertical fracture of the axis body: surgical treatment of a rare condition. Minim Invasive Neurosurg 1998;41(2):93–96 Bohay D, Gosselin RA, Contreras DM. The vertical axis fracture: a report on three cases. J Orthop Trauma 1992;6(4):416–419 Lozano-Requena JA, Pina-Medina A, Aracil-Silvestre J, Torro-Belenguer V, Baixauli-Castella F. Sagittal fracture of the second cervical vertebral body. Int Orthop 1994;18(2):114–115 Marotta TR, White L, TerBrugge KG, Spiegel SM, Stevens JK, Tator CM. An unusual type of hangman's fracture. Neurosurgery 1990;26(5):848-850, discussion 850–851 Jakim I, Sweet MB. Transverse fracture through the body of the axis. J Bone Joint Surg Br 1988;70(5):728–729 Maki NJ. A transverse fracture through the body of the axis. A case report. Spine 1985;10(9):857–859 Craig JB, Hodgson BF. Superior facet fractures of the axis vertebra. Spine 1991;16(8):875–877

Applied anatomy of a minimally invasive muscle-splitting approach to posterior C1–C2 fusion: an anatomical feasibility study

To describe the applied anatomy of a minimally invasive muscle-splitting approach used to reach the posterior aspect of the C1-C2 complex. Atlantoaxial fusion using a midline posterior approach and polyaxial screw and rod system is widely used. Although minimally invasive variations of this technique have been recently reported, the complex applied anatomy of these approaches has not been described. The C1-C2 complex represents an unique challenge because of its bony and vascular anatomy. In this study, the applied anatomy and feasibility of this technique are examined on cadavers. The microsurgical anatomy of the upper cervical spine is examined on a formalin-fixed and on a fresh cadaver. The muscle-splitting approach is performed on 12 fresh cadavers using this technique. The minimally invasive muscle-splitting approach is described in detail. Relevant anatomy and bony landmarks that aid screw placement in C1 and C2 could be well visualized. Using this approach, we were able to reach the lateral mass of the atlas and the inferior articular process and pars interarticularis of the axis in all of the nine cadavers. We placed mini polyaxial screws in C1 lateral mass and C2 pars interarticularis in four cadavers according to the technique described by Harms and Melcher. Using this approach, it was possible to reach the posterior aspect of C1 and C2; the relevant anatomy needed to perform a C1-C2 fusion could be well visualized.

Surgical management of the fractures of axis body: indications and surgical strategy

The axis body fractures are relatively uncommon and have a variety of presentations. Surgical management to them has been only reported as case reports or included as a minor part of clinical management. The objective of this study is to summarize the indications for surgery and report the clinical outcome of surgical treatment based on different fracture patterns. A retrospective analysis of 28 consecutive patients presenting with the axis body fractures was undertaken. The indications for surgical treatment were defined as: (1) fractures associated with instability of adjacent joints; (2) irreducible displaced superior articular facet fracture; (3) fractures resulting in spinal cord compression. The fractures were classified as sagittal, coronal, transverse and lateral mass fracture. One of the following surgical procedures was applied according to the fracture pattern: posterior C1-C2 pedicle screws fixation and fusion (I); posterior C1-C3 screws fixation and fusion (II); posterior osteosynthesis with C2 transpedicular half-thread lag screws (III). 13 patients were successfully managed operatively. Two transverse and two unilateral lateral mass fractures were treated with surgical procedure I, five sagittal fractures with II, four coronal fractures with III. Complications of malposition of screws and neurologic deficit did not occur during operation. Satisfactory reduction and bony union were demonstrated on postoperative radiographics. Conservative treatment is still advocated as primary management for most axis body fractures. But for patients with obvious adjacent joints instability or irreducible displaced superior articular facet fracture, surgical intervention based on the different fracture pattern is necessary.

Efficacy of rhBMP-2 Versus Iliac Crest Bone Graft for Posterior C1–C2 Fusion in Patients Older Than 60 Years

Few studies have specifically examined the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)/absorbable collagen sponge (ACS) in posterolateral lumbar spine fusion. The purpose of this study was to report the clinical outcomes in elderly patients treated with posterior C1-C2 fusion with iliac crest bone graft (ICBG) plus rhBMP-2/ACS vs ICBG alone. One hundred forty patients older than 60 years were enrolled in this prospective, randomized trial and underwent instrumented C1- C2 fusion. Patients were divided into 2 groups based on fusion material. The ICBG group comprised patients who received ICBG alone, and the rhBMP-2/ACS group comprised patients who received ICBG plus rhBMP-2/ACS. The groups were compared based on operative time, estimated blood loss, hospital length of stay, clinical results, perioperative complications, fusion rate, fusion time, and revision rate. There were no significant differences in operative time, estimated blood loss, length of stay, and intraoperative complications between the 2 groups. Improvements in visual analog scale scores and Japanese Orthopaedic Association scores over the 2-year follow-up period were similar between groups. The fusion rate was 82.4% (56 of 68) in the rhBMP-2/ACS group and 78.7% (52 of 66) in the ICBG group (P=.782). Mean fusion time was 11 days shorter in the rhBMP-2/ACS group (81.8±29.4 days) than in the ICBG group (92.9±23.7 days) (P=.034). There were more wound complications requiring treatment in the rhBMP-2/ACS group (n=6; 8.8%) than in the ICBG group (n=2; 3.0%), although this was not statistically significant (P=.118). The use of rhBMP-2/ACS for posterior C1-C2 fusion appears to result in a relatively shorter fusion time, but there may be an increased risk of posterior cervical wound complications.