Transoral Decompression Research Articles

Surgical strategies for the treatment of os odontoideum with atlantoaxial dislocation.

OBJECTIVE This study aimed to compare the clinical results of using posterior fixation and fusion with or without anterior decompression to treat os odontoideum with atlantoaxial dislocation. METHODS Twenty-five consecutive patients with os odontoideum were included in this study. Sixteen patients with reducible atlantoaxial dislocation were treated by single-level posterior fusion and stabilization; the other 9 were treated with posterior fusion and stabilization combined with transoral decompression. Pre- and postoperative CT scans and MR images were obtained. RESULTS Twenty-four patients were followed for 24-54 months (average 36.5 months). Postoperative CT scans indicated that all pedicle screws were placed satisfactorily except in 2 cases, in which the screws slightly penetrated the transverse foramen. Postoperative MR images demonstrated that sufficient decompression of the spinal cord was obtained in all patients. Complications included 1 case each of pedicle screw breakage, pharynx ulcer, and persistent pharynx discomfort. Statistical analysis of all cases revealed that mean Japanese Orthopaedic Association scores improved from a preoperative score of 10.2 (range 7-13) to a postoperative score of 15.6 (range 11-18). CONCLUSIONS Patients who have os odontoideum with a reducible atlantoaxial dislocation can be effectively treated with single-level posterior fusion and stabilization. Combined transoral decompression and posterior fusion and stabilization is recommended for those with irreducible atlantoaxial dislocation.

Case for transoral decompression of craniovertebral junction and C1 and odontoid for fixed atlanto axial dislocation and basilar invagination

Transoral decompression of the craniovertebral junction is an established and safe method. Lateral atlanto-axial joints may be distracted and then fused posteriorly in some cases. The decision should be individualized based on the imaging and clinical picture.

Atlantoaxial Joint Distraction with a New Expandable Device for the Treatment of Basilar Invagination with Preservation of the C2 Nerve Root: A Cadaveric Anatomical Study.

Atlantoaxial joint distraction has been advocated for the decompression of the brain stem in patients affected by basilar invagination, avoiding direct transoral decompression. This technique requires C2 ganglion resection and it is often impossible to perform due to the peculiar bony anatomy. We describe a cadaveric anatomical study supporting the feasibility of C1-C2 distraction performed with an expandable device, allowing easier insertion of the tool and preservation of the C2 nerve root. In five adult cadaveric specimens, posterior atlantoaxial surgical exposure was performed and an expandable system was inserted within the C1-C2 joint. The expansion of the device, leading to active distraction of the joint space, together with all the surgical steps of the technique was recorded with anatomical pictures and the final results were checked with a computed tomography (CT) scan. Insertion of the device was easily performed in all cases without anatomical conflict with the C2 ganglion; CT scans confirmed the distraction of the C1-C2 joint. This cadaveric anatomical study confirms the feasibility of the introduction of an expandable and flexible device within the C1-C2 joint, allowing it's distraction and preservation of the C2 ganglion.

Surgical Treatment of Occipitocervical Dislocation with Atlas Assimilation and Klippel-Feil Syndrome Using Occipitalized C1 Lateral Mass and C2 Fixation and Reduction Technique

To introduce and assess a surgical treatment of occipitocervical (OC) dislocation with atlas assimilation and Klippel-Feil syndrome (KFS) using occipitalized C1 lateral mass and C2 fixation and reduction technique. From January 2007 to August 2013, 58 symptomatic patients with OC dislocation and KFS of C2-3 congenital fusion and atlas assimilation were surgically treated in our institution via this technique. After opening the C1-2 facet joints via a posterior approach, OC reduction was conducted by intraoperative manipulation and C1 lateral mass and C2 pedicle screw and rod fixation. The instrument position, fusion status, and clinical outcome were analyzed. The average follow-up was 36 months (range, 18-52 months). Radiologically, effective reduction was achieved in 56 patients (96.6%) and <50% reduction in 2 (3.4%) who had additional transoral decompression. Neurologic improvement and solid bone fusion were achieved in all patients. The clinical symptoms improved for all patients, with the averaged Japanese Orthopedic Association myelopathy scores increasing from 11.5 to 15.6 (P < 0.01). In patients with OC dislocation and KFS of C2-3 fusion and atlas assimilation, posterior manipulative reduction combined with occipitalized C1 lateral mass and C2 fixation provides a reliable and effective treatment.

Craniovertebral junction anomalies: When is resurgery required?

Craniovertebral junction (CVJ) abnormalities, such as atlantoaxial dislocation (AAD) with or without basilar invagination (BI), with or without associated Chiari malformation (CM), may cause a high cervical myelopathy. Occasionally, mechanical factors such as inadequate canal decompression, torticollis, and/or scoliosis may lead to lack of improvement following the primary surgery. Furthermore, implant-related factors, requiring implant revision/removal, or the presence of surgical site infections may cause the patient to undergo resurgery. This study was aimed at highlighting the underlying etiopathogenesis of resurgery following the primary surgery undertaken in CVJ abnormalities. This was a retrospective study from a tertiary care referral institute focusing on 414 operated cases of CVJ anomalies. The data of 55 patients who underwent resurgery included their clinicoradiological assessment and operative records. The inclusion criteria included failed primary procedure, repeat procedure for construct failure, infection at the surgical site, or wound dehiscence. Pure CM patients without bony anomalies were excluded from the study. A total of 137 procedures were performed in 55/414 (13%) patients. Causes of resurgery could be divided into ventral [redo or denovo transoral decompression (TOD) or wound-related complications, n = 33, 40.2%] and dorsal causes (implant-related factors/wound infections, n = 49, 59.8%). De novo TOD was done in persisting myelopathy following posterior fusion (PF) with C1-2 distraction (n = 15,18.3%,). Redo TOD was done for residual anterior bony compression [n = 8, 9.6%, OR 0.61; [CI = 0.20-1.86]. Causes for oral wound reexplorations (n = 10, 12.2%) included velopharyngeal insufficiency, wound resuturing, oral bleeding, and cerebrospinal fluid (CSF) leak. Dorsal causes included: (A) Implant factors (n = 27, 32.7%) and (B) neck wound reexplorations (n = 22, 26.8%). Presence of subaxial spine scoliosis, torticollis, and asymmetric joints increased the incidence of reexploration. Occipitocervical fusion rather than C1-2 fusion was more prone towards construct loosening. Patients undergoing distraction with PF may require transoral surgery due to persisting myelopathy, especially in the presence of torticollis, scoliosis, and symmetrical joints. Single stage TOD+PF increases the chances of implant infection due to tissue contamination, bacteremia, or transfacetal migration of microbes. Chronic/recurrent sinus is usually a harbinger of deeper infection and can be cured with implant removal.

Posterior Reduction of Fixed Atlantoaxial Dislocation and Basilar Invagination by Atlantoaxial Facet Joint Release and Fixation: A Modified Technique With 174 Cases.

Treatment of fixed atlantoaxial dislocation (AAD) with basilar invagination (BI) is challenging. To introduce a modified technique to reduce fixed AAD and BI through a posterior approach. From 2007 to 2013, 174 patients with fixed AAD and BI underwent surgical reduction by posterior atlantoaxial facet joint release and fixation technique. There was 1 death in the series, and 3 patients were lost to follow-up. The follow-up period ranged from 12 to 52 months (mean: 35.2 months) for the remaining 170 patients. Neurological improvement was observed in 168 of 170 patients (98.8%), and was stable in 1 (0.06%) and exacerbated in 1 (0.06%), with the Japanese Orthopedic Association scores increasing from 11.4 preoperatively to 15.8 postoperatively (P < .01). Radiologically, complete or >90% reduction was attained in 107 patients (62.9%), 60% to 90% reduction was attained in 51 patients (30%), and <50% reduction was attained in 12 patients (7.1%), who underwent additional transoral decompression. Complete decompression was demonstrated in all 170 patients. Solid bony fusion was demonstrated in 167 patients at follow-up (98.2%). This series showed the safety and efficacy of the posterior C1-2 facet joint release and reduction technique for the treatment of AAD and BI. Most fixed AAD and BI cases are reducible via this method. In most cases, this method avoids transoral odontoidectomy and cervical traction. Compared with the occiput-C2 screw method, this short-segment C1-2 technique exerts less antireduction shearing force, guarantees longer bone purchase, and provides more immediate stabilization.

Giant cell tumor of axis: A rare entity

Giant cell tumor of the bone accounts for 4–;5% of all primary bone tumors. Spine is the fourth common site for their occurrence and axis is a relatively rare site. A case of giant cell tumor of axis in a 17-year-old male is hereby reported. The patient underwent transoral decompression and posterior fusion. Postoperatively patient had no neurological deficit and biopsy revealed the tumor as giant cell tumor.

Comprehensive drilling of the C1-2 facets to achieve direct posterior reduction in irreducible atlantoaxial dislocation.

The cause of irreducibility in irreducible atlantoaxial dislocation (AAD) appears to be the orientation of the C1-2 facets. The current management strategies for irreducible AAD are directed at removing the cause of irreducibility followed by fusion, rather than transoral decompression and posterior fusion. The technique described in this paper addresses C1-2 facet mobilization by facetectomies to aid intraoperative manipulation. Using this technique, reduction was achieved in 19 patients with congenital irreducible AAD treated between January 2011 and December 2013. The C1-2 joints were studied preoperatively, and particular attention was paid to the facet orientation. Intraoperatively, oblique C1-2 joints were opened widely, and extensive drilling of the facets was performed to make them close to flat and parallel to each other, converting an irreducible AAD to a reducible one. Anomalous vertebral arteries (VAs) were addressed appropriately. Further reduction was then achieved after vertical distraction and joint manipulation. Adequate facet drilling was achieved in all but 2 patients, due to VA injury in 1 patient and an acute sagittal angle operated on 2 years previously in the other patient. Complete reduction could be achieved in 17 patients and partial in the remaining 2. All patients showed clinical improvement. Two patients showed partial redislocation due to graft subsidence. The fusion rates were excellent. Comprehensive drilling of the C1-2 facets appears to be a logical and effective technique for achieving direct posterior reduction in irreducible AAD. The extensive drilling makes large surfaces raw, increasing fusion rates.

Transoral Decompression and Posterior Stabilization in Fixed Anterior Pathology of the Craniocervical Junction

Introduction Management of the anterior compressive pathology of the craniovertebral junction (CVJ) is complex and demanding. We review our experience with the transoral surgical decompression of fixed anterior CVJ lesions, with particular attention to the decision making and to the indication for a consecutive stabilization. Patients and Methods Retrospective study (2000–2013) of 47 consecutive patients (14 males and 13 females). Mean age was 59.2 years (range, 32–82 years). Encountered lesions were rheumatoid arthritis with pannus (29, 9 of which with associated cranial settling), ankylosing spondylitis (four), tumors (seven: six extradural chordomas/chondrosarcomas and one metastasis), odontoid fractures with hypoporosis, and rotational instability (seven). Patients presented with a variety of following symptoms: high cervical pain (82%), varying degrees of quadriparesis (64%), lower cranial nerve deficits (23%), and central cord syndrome with neurogenic bladder (14%). All patients underwent one-stage transoral decompression and consecutive posterior atlantoaxial or occipitocervical stabilization. Clinical evaluation was made pre- and postoperatively using the Ranawat score. Follow-up period ranged between 6 and 48 months (average, 22 months). Results According to the Ranawat score, we had 21 grade I patients, in 20 of which pain was eradicated, 10 grade II patients, 8 of which passed to grade I, 11 grade IIIA patients, of which 6 passed to grade I and 5 to grade II, and 5 grade IIIB patients of which 4 passed to grade IIIA. In seven patients, the transarticular screws crossed the anterior cortex of the atlas, without clinical manifestations. In five patients, complete reduction of the C1–C2 rotation was not possible, because of the chronic nature of the defect. Surgical morbidity occurred in five cases (three dural tears and two occipital wound infections). There were two perioperative deaths ([a] dural rupture, pneumoencephaly, meningitis, and massive pulmonary embolism, [b] pulmonary infection, and cardiorespiratory arrest). Conclusion Successful and stable decompression of the CVJ requires extensive preoperative evaluation, appropriate tailoring, and adequate expertise. The transarticular C1–C2 fixation is a safe and effective stabilization method when the atlanto-occipital joints remain competent. Complications appear mostly in patients with rotational deformity of the C1–C2 complex. Patients with clinical and radiological findings of myelopathy improve less even if surgery is successful.

Posterior-Only Approach for Reduction of Occipitocervical Instability with Vertical Migration of the Dens

Introduction Occipitocervical instability with vertical odontoid migration is a rare but potentially debilitating anomaly. Anterior decompression followed by posterior stabilization is commonly used to address the pathology, but the former is associated with significant morbidity. More recently, posterior-only techniques have been described to obtain reduction and stabilization for nonfused cases of cranial settling. Patients and Methods Retrospective analysis of seven cases of patients (four males, three females, age range 34–73 years) who suffered from occipitocervical instability with reducible vertical dislocation of the odontoid in the setting of various underlying pathology. Six patients were myelopathic preoperatively. The neurological status was classified according to the Nurick scale. Pain was assessed according to the Visual Analog Scale. Radiological measurements included preoperative and postoperative evaluation of the position of the tip of the odontoid process in relation to Chamberlain, McGregor, McRae, and Wackenheim lines, and measurement of the Ranawat line, the clival angle, and the Klaus height index. Follow-up ranged from 8 to 42 months. Results Five patients improved neurologically, and one remained stable. Pain improved significantly in these patients, and was completely eliminated in three of them. Obvious reduction of the deformity was demonstrated by the postoperative radiological craniometric measurements. One patient did not improve neurologically. Postoperative imaging revealed a very small reduction with practically unchanged ventral compression of the cord. He underwent transoral decompression at a second stage. No patient suffered from severe complications. No screw pullout, loosening, or fracture of implant has been observed so far. Conclusion Modern screw–rod systems enable intraoperative correction of nonfused deformity and indirect decompression of the cervicomedullary junction obviating the need for ventral decompression or preoperative traction. Patient selection is critical to ensure successful application of the reduction maneuvers.

Craniovertebral tuberculosis in children: experience of 23 cases and proposal for a new classification.

The aim of this study was to review cases of paediatric patients with craniovertebral junction (CVJ) tuberculosis with a view to try and stratify the cases into different groups which would help plan treatment and hence develop a protocol for treatment of a fairly uncommon condition still widely seen in the developing world. Twenty-three cases of paediatric craniovertebral tuberculosis had their clinical features and radiology reviewed. The treatment plan in each case was analyzed according to their presentation. The results of treatment after 1 year were assessed in each case. The clinical presentations varied from neck pain with hypoglossal nerve palsy to frank spastic quadriparesis, and frank instability at the atlanto-axial junction was seen in five out of 23 patients. Cold abscesses were seen in 18/23 cases, and severe torticollis was the presentation in 6/23. We graded the children with this condition into three groups: 1) those with instability and gross neurodeficit who required early operative intervention (1 needed trans-oral decompression with posterior fixation and 4 required posterior fixation) 2) those who had severe torticollis and large cold abscesses who were treated with trans-oral aspiration of cold abscess followed by neck immobilization (6/23) and 3) those who did not have significant neck muscle spasm or torticollis and who were treated with immobilization alone (12/23). Only one child in group 3 required delayed intervention for instability which developed after completion of the course of anti-tubercular medication. We concluded that children with craniovertebral tuberculosis should be treated according to their clinical presentation coupled with evidence of radiological instability. Those with gross deficit and instability need early stabilization, those with minimal deficit and no instability but severe pain or torticollis need aspiration of the cold abscess with external immobilization, whereas those without deficit, instability or severe pain may be managed by external orthoses alone. Of course, medical treatment for tuberculosis is necessary in each case.

Risk stratification of vertebral artery vulnerability during surgery for congenital atlanto-axial dislocation with or without an occipitalized atlas.

Variability in dimensions and course of vertebral artery (VA) makes it vulnerable to injury during surgery for congenital atlanto-axial dislocation (AAD) with or without an occipitalized atlas. This prospective study attempts to define anatomical variations that render VA at the craniovertebral junction (CVJ) vulnerable to injury during transoral decompression and posterior stabilization procedures; and, to propose a classification that helps in preoperative risk stratification. A prospective study. 104 patients (65 with AAD; 39 controls) underwent a three-dimensional multiplanar computed tomographic angiogram to study anatomical variations in VA size, course, and anomalous medial deviation as well as in the type of axial isthmus and rotational deformity/tilt at the CVJ. The VA/foramen transversarium diameter; "stretched loop" sign of VA; and C1-2 facet joint angle were also assessed. A medial VA deviation that brought it in close proximity to the trajectory of the surgical approach was evaluated (P ≤ 0.05 significant). An increased predisposition to VA injury was present in 23 (35.4%) patients (persistent first intersegmental artery [n = 20; 30%]; fenestrated VA [n = 1; 1.53%], and low-lying posterior inferior cerebellar artery [n = 2; 3.0%]) where VA crossed the C1-2 facet joint; 8 (12%) with an anomalous medial deviation; 12 (18%) with a high-riding VA at C2 and a narrow axial isthmus; and 13 (20%) with rotation/tilt at the CVJ. A normal score of 5 was obtained in 21 patients; and a score of 6-9 (that progressively indicated an increased vulnerability of VA to iatrogenic injury) in 44 patients. The "AAD with an occipitalized atlas" group was associated with a significant medial deviation of VA (right: P = 0.00 and left: P = 0.001). A preoperative detailed risk assessment of anatomical variations in the size and course of VA at the CVJ significantly reduces chances of its iatrogenic injury.

C1 lateral mass screw placement in occipitalization with atlantoaxial dislocation and basilar invagination: a report of 146 cases.

Retrospective study of 146 patients with the diagnosis of occipitalization, atlantoaxial dislocation (AAD) and basilar invagination, using a novel surgical treatment strategy. To introduce a novel fixation and reduction technique. Atlas occipitalization associated with basilar invagination often result in fixed AAD that need reduction and occipitocervical fixation. The widely used occipitocervical fixation with suboccipital screws has several limitations such as the poor screw purchase in maldevelopment of the occipital bone, limited area available for implants in previous suboccipital craniectomy. The placement of occipitalized C1 lateral mass screw is an alternative option. From June 2007 to June 2013, 146 patients of occipitalized atlas with fixed AAD and basilar invagination, underwent fixation and reduction via C1 lateral mass and C2 pars/pedicle screw. A total of 143 patients achieved the follow-up in the range from 6 months to 4 years (average, 30 mo). Neurological improvement was seen in all the 143 patients, with the averaged Japanese Orthopedic Association scores increasing from 11.6 to 15.5. Radiographical evaluation showed that solid bony fusion was achieved in all patients, and complete reduction was attained in 95 patients, and partial reduction (>60%) in 40 patients, and no effective reduction in 8 patients who had additional transoral decompression. Magnetic resonance imaging demonstrated that the ventral cervicomedullary compression was relieved in all patients. Although technically demanding, the C1 lateral mass placement in occipitalization is very useful in the rescue situation where more conventional stabilization alternatives are not technically possible, or as routine occipitocervical stabilization. It provides firm stabilization offering an optimum situation for bony fusion, and meanwhile the effective reduction of fixed AAD and basilar invagination. An extremely high fusion rate can be expected with minimal complications and minimal postoperative immobilization with this technique.

Treatment of basilar invagination with atlantoaxial dislocation: atlantoaxial joint distraction and fixation with transoral atlantoaxial reduction plate (TARP) without odontoidectomy.

Although direct transoral decompression and one-stage posterior instrumentation can obtain satisfactory cord decompression for the treatment of basilar invagination with atlantoaxial dislocation, surgical injuries run high as combinative anterior-posterior approaches were necessary. Furthermore, the complications will rise notably when involvement of dens and/or clivus in the decompression necessitates relatively complicated surgical techniques. First initiated in 2005, transoral atlantoaxial reduction plate (TARP) works as an internal fixation for the treatment of basilar invagination with irreducible atlantoaxial dislocation. Therefore, this article aimed to describe several operative experiences about this approach, which has delivered successful decompression, fixation and fusion. 21 consecutive patients with basilar invagination underwent the TARP operation. The pre- and postoperative medulla-cervical angles were measured and compared. The JOA scores of spinal cord function were calculated pre- and post-operatively. 20 cases (20/21) were followed up to average 12.5 months. Symptoms of all the 20 cases were relieved in different degrees. The postoperative imaging showed the odontoid processes obtained ideal reduction and the internal fixators were all in good position. The medulla-cervical angle was correctd from an average (± standard deviation) 128.7° + 11.9° (n = 20) before surgery to 156.5° + 8.1° (n = 20) after surgery (P < 0.01). The average preoperative and postoperative Japaneses Orthopedic Association scores were 11.25 (n = 20) and 15.9 (n = 20), respectively, indicating 76 % improvement. Screw-loosening was observed in one patient due to severe osteoporosis. After a revised operation with a TARP in another size, the neurological symptoms showed no obvious improvements. Then the treatment was terminated. The TARP operation and intra-operative traction could reduce the odontoid process superiorly migrating into the foramen magnum, directly ease the ventral compression of spinal cord, and fix the reduced atlantoaxial joints through a single transoral approach without the need of a posterior operation. In this stury, 21 patients were evaluated and 20 did well with TARP operation. The preliminary clinical result was satisfactory.

Treatment of Irreducible Atlantoaxial Dislocation with C1-2 Sublaminar Cable-Dragged Reduction and Screw Fixation

Introduction Irreducible atlantoaxial dislocation (IAAD) is defined as the fixed displacement of C1-2 which is difficult to reach anatomic reduction, even with strong cranial skeletal traction under general anesthesia. The most frequently used method to treat symptomatic IAAD is transoral decompression or release combined with posterior fixation following preoperative cranial traction. However, those procedures are accompanied with high morbidity and mortality. We assumed that the inability to be reduced through cranial traction does not necessarily mean an irreducible dislocation, for the force exerted by cranial traction is oriented mainly upward, leading to an indirect reducing effect. Therefore, a new reduction strategy, called C1-2 sublaminar cable-dragged technique, has been developed to exert a straight backward force on the atlas to achieve an anatomic reduction followed by C1-2 screw fixation in a single stage via a posterior approach. The purpose of the present article is to report the early results of application of this method. Materials and Methods Thirty-two consecutive patients with IAAD, who underwent C1-2 posterior cable-dragged reduction and fixation, were retrospectively reviewed with minimum 2-year follow-up. Patient's mean age was 43.6 ± 19.4 years (range, 31-68). Anatomic reduction was achieved by passing a double 18-gauge titanium cable through the arch of C1 and lamina of C2. The cable was then retracted and tightened temporarily with a cable tensioner. Once satisfactory reduction was achieved and confirmed by C-arm radiography, fixation with C1 lateral mass screw and C2 pedicle screw was routinely performed. Then an autologous cancellous bone was grafted between the posterior arch of C1 and lamina of C2 using a modified Brooks-Jenkins procedure (Fig. 1). Lateral radiograph, 3D-CT, and MRI were obtained before surgery and at 3, 6, 12, and 24 months after surgery. Bony fusion was evaluated in flexion and extension lateral radiographs. Clinical symptoms were assessed with NDI and Frankel classification. Results The average follow-up period was 16.4 months. Radiographic evaluation of the group at follow-up showed 30 complete and 2 partial reductions, and satisfactory decompression in all cases (Fig. 2). Surgical complications, such as dural tear, laminar fracture, and spinal cord injury did not occur in any cases. The relief of occipital pain showed in 29 patients (90.6%). With regard to neurological recovery after surgery, 24 patients (75.0%) showed improvement by at least one level of Frankel criteria. Bony union was achieved in 31 patients (96.9%). Subaxial lesion occurred in four cases (12.5%), but additional surgery was not required in any cases. Conclusion Cable-dragged reduction and screw fixation are almost as effective for reduction as anterior release but is less invasive and risky. It could provide a high fusion rate and relief of pain. We suggest the use of a braided cable wire because it is soft and relatively safe to pass, resists fatigue well, and provides excellent fixation. However, there is little risk of vertebral artery and spinal cord injury. In conclusion, we recommend this new technique for IAAD patients with intact posterior arch of atlas. Disclosure of Interest None declared

Ganglion cyst of the cruciate ligament with atlantoaxial subluxation

Ganglion cysts of the cruciate ligament are rare and sometimes asymptomatic. The authors present three cases of ganglion cysts of the cruciate ligament with atlantoaxial subluxation, which has rarely been reported previously. Generally, ganglion cysts of the cruciate ligament are reported as case reports. Several theories regarding the process of cyst formation and the development of treatment options have been described. However, trans-oral decompression with total removal of the cyst may be one of the options for treatment of this kind of disease. A retrospective review of three patients, two female and one male patient, with a mean age of 68 years was conducted. The operation performed was a trans-oral decompression with cyst removal for all patients. Clinical outcomes were evaluated after the operation. All patients underwent trans-oral decompression with total removal of the cyst, followed by posterior fusion and pathologic examination of the cyst, revealing myxoid stroma with an absence of synovial linings. The ganglion cysts and synovial cysts of the cruciate ligament are two different diseases with different presentation, pathogenesis, pathophysiology, and pathologic findings.

Reduction techniques in the management of atlantoaxial subluxation.

Background:The traditional approach to atlantoaxial subluxation which is irreducible after traction is transoral decompression and reduction or odontoid excision and posterior fixation. Transoral approach is associated with comorbidities. However using a posterior approach a combination of atlantoaxial joint space release and a variety of manipulation procedures, optimal or near optimal reduction can be achieved. We analysed our results in this study based on above procedure.Materials and Methods:66 cases treated over a 5 year period were evaluated retrospectively. Three cases treated by occipito cervical fusion were not included in the study. The remaining 63 cases were classified into three types. All except two cases were subjected to primary posterior C1-C2 joint space dissection and release followed by on table manipulation which was tailored to treat the type of atlantoaxial subluxation. Optimal or near optimal reduction was possible in all cases. An anterior transoral decompression was needed only in two cases where a bony growth (callus) between the C1 anterior arch and the odontoid precluded reduction by posterior manipulation. All cases then underwent posterior fusion and fixation procedures. Patients were neurologically and radiologically evaluated at regular followups to assess fusion and stability for a minimum period of 6 months.Results:Of the 63 cases who underwent posterior manipulation, 49 cases achieved optimum reduction and the remaining 14 cases showed near optimal reduction. Two cases expired in the postoperative period. None of the remaining cases showed neurological worsening after the procedure. Evaluation at 6 months after surgery revealed good stability and fusion in all except three cases.Conclusion:Atlantoaxial joint release and manipulation can be used to achieve reduction in most cases of atlantoaxial subluxation, obivating the need of transoral odontoid excision.

Syndromic versus nonsyndromic atlantoaxial dislocation: do clinico-radiological differences have a bearing on management?

This prospective study attempts to study the clinico-radiological differences between patients with syndromic AAD (SAAD), non-syndromic AAD (NSAAD), and AAD with Klippel-Feil anomaly (AADKFA) that may impact management. In 46 patients with AAD [SAAD (including Morquio, Down, Larson and Marshall syndrome and achondroplasia; n = 6); NSAAD(n = 20); and, AADKFS (n = 20)], myelopathy was graded as mild (n = 17, 37 %), moderate (15, 32.5 %) or severe (14, 30.5 %) based on Japanese Orthopaedic Association Score modified for Indian patients (mJOAS). Basilar invagination (BI), basal angle, odontoid hypoplasia, facet-joint angle, effective canal diameter, Ishihara curvature index, and angle of retroversion of odontoid and vertebral artery (VA) variations were also studied. Clinico-radiological differences were assessed by Fisher's exact test, and mean craniometric values by Kruskal-Wallis test (p value ≤ 0.05 significant) Incidence of irreducible AAD in SAAD (n = 0), NSA AD (11.55 %) and AADKFS (n = 18.90 %) showed significant difference (p = 0.01). High incidence of kyphoscoliosis (83 %) and odontoid hypoplasia (83 %) in SAAD, and assimilated atlas and BI in NSAAD and AADKFA groups were found. In AADKFA, effective canal diameter was significantly reduced(p = 0.017) with increased Ishihara index and increased angle of odontoid retroversion; 61 % patients had VA variations. Thirty-five patients underwent single-stage transoral decompression with posterior fusion (for irreducible AAD) or direct posterior stabilization (for reducible AAD). Postoperative mJOAS evaluation often revealed persistent residual myelopathy despite clinical improvement. Myelopathy is induced by recurrent cord trauma due to reducible AAD in SAAD, and compromised cervicomedullary canal diameter in NSAAD and AADKFA. SAAD in children may be missed due to incomplete odontoid ossification or coexisting angular deformities. In AADKFA, decisions regarding vertebral levels to be included in posterior stabilization should take into consideration intact intervening motion segments and compensatory cervical hyperlordosis. Following VA injury, endovascular primary vessel occlusion/stenting across pseudoaneurysm preempts delayed rehemorrhage.

Treatment of complicated congenital Arnoid-Chiari's malformation by occipitocervical fixation and bone graft fusion

Objective To investigate the effects of occipitocervical fixation and bone grafting fusion for the treatment of complicated congenital occipitocervical malformations.Methods A retrospective analysis of 21 cases of complicated occipitocervical malformation patients was performed.Seventeen cases underwent posterior cranial decompression bone grafting and fixation of occipital cervical fusion.Four cases underwent soft tissue and bony tissue resection,decompression of odontoid process reset decompression,posterior foramen magnum decompression,bone grafting and fixation of occipital cervical fusion.All patients were followed up by 3 months to 3 years.Results For the patient with atlantoaxial dislocation and the presence of intra-axial ventral,dorsal compression,good effects could be achieved through soft tissue and bony tissue resection,posterior foramen magnum decompression,bone grafting and fixation of occipital cervical fusion.There was no relationship between dural matter repair,cerebellum tonsil resection and final effects.For the patient with segmental syringomyelia,spinal cord subarachnoid drainage should be done.Conclusions Different operation scheme should be considered according to the anatomic variation and formation mechanism of complicated occipitocervical malformations to improve the long-term surgical effects. Key words: Congenital complex occipital malformation; Posterior fossa decompression; Fusion with iliac bone graft and internal fixation; Transoral approach decompression

Retrodental Mass in Rheumatoid Arthritis

A retrospective investigation of the retrodental mass secondary to rheumatoid arthritis (RA). To propose a new classification of the retrodental mass in RA, and to evaluate their resorption processes and surgical procedures. The retrodental mass secondary to RA has long been recognized as pannus formation. It is also known that pannus will disappear or radically reduce after stabilization of the atlantoaxial segment. The past reports, however, leave unanswered the following question; are there other types of mass with significantly different degeneration processes from the pannus? The need for anterior transoral decompression is still controversial. Eleven patients with retrodental masses in RA were retrospectively analyzed. They underwent posterior fusion without decompression for atlantoaxial subluxation and occipitocervical fusion with decompressive laminectomy of the atlas for vertical subluxation. All patients had neurological, radiologic, and magnetic resonance imaging (MRI) evaluations both before and after surgery. MRI study was performed preoperatively and at 1-month interval after surgery until the mass had disappeared or stopped further reduction. This study identified 3 distinctive types in the rheumatoid retrodental mass on MRI. Type 1 displayed high intensity on T2 and low intensity on T1-weighted MRI or the pattern specific to pannus. Type 2 was identified with low intensity on T2-weighted MRI or pattern specific to pseudotumor. Type 3 displayed a combination of high and low intensity on T2-weighted images or indication that the mass was the mixture of pannus and pseudotumor. All the masses of types 1 and 3 disappeared within 1 month of surgery. The process in type 2 was found a few months slower. In all 11 cases, myelopathy improved postoperatively to the status before the emergence of the symptom. This article recognized 3 distinctive types of the retrodental mass in RA; type 1 (pannus), type 2 (pseudotumor), type 3 (mixed). It further concludes in all types of the retrodental mass associated with atlantoaxial subluxation secondary to RA, posterior fusion without decompression can achieve improvement of the myelopathy. In type 2 associated with vertical subluxation, on balance between calculable benefits and high risks of anterior transoral decompression, the authors prefer to opt for occipitocervical fusion with decompressive laminectomy of the atlas.