Transdural Approach for Resection of Craniovertebral Junction Cysts: Case Series

BACKGROUND

Craniovertebral junction (CVJ) cysts, including retro-odontoid pseudotumors, are challenging pathologies to treat and manage effectively. Surgical intervention is indicated when these lesions result in progressive myelopathy, intractable pain, or instability.

OBJECTIVE

To present a case series of older patients who underwent successful resection retro-odontoid lesions using transdural approach.

METHODS

A single-center, retrospective observation study of older patients who underwent transdural resection of CVJ cysts at a single institution was performed. Summary demographic information, clinical presentation, perioperative and intraoperative imaging, and Nurick scores were collected and analyzed.

RESULTS

Eight patients were included (mean age [±SD] 75.88 ± 9.09 years). All patients presented with retro-odontoid lesions resulting in severe cervical stenosis, cord compression, and myelopathy. The mean duration of surgery was 226 ± 83.7 minutes. The average intraoperative blood loss was 181.2 cc. The average hospital stay was 4.5 days ± 1.3 (range, 3-7 days). The average follow-up time was 12.5 ± 9.5 months. No intraoperative complications were encountered. The Nurick classification score for myelopathy improved at the final postoperative examination (2.38 ± 1.06 vs 1 ± 1.07). Three patients demonstrated a pre-existing deformity prompting an instrumented fusion. Both computed tomography and MRI evidence of complete regression of retro-odontoid cyst were noted in all patients on the final follow-up.

CONCLUSION

Posterior cervical transdural approach for ventral lesions at the CVJ is a safe and effective means of treating older patients with progressive myelopathy. This technique provides immediate spinal cord decompression while limiting neurological complications commonly associated with open or endoscopic anterior transpharyngeal approaches.

MR documented craniocervical ligamentous injury at age 18 months: delayed formation of OS odontoideum. Complex management issues. Case-based review

OBJECTIVE

There are two separate theories regarding the genesis of os odontoideum: congenital and post-traumatic. Trauma documentation in the past has been the presence of a normal odontoid process at the time of initial childhood injury and subsequent development of the os odontoideum. True MR documentation of craniocervical injury in early childhood and subsequent os odontoideum formation has been very rare.

METHODS

An 18-month-old sustained craniocervical ligamentous injury documented on MRI with transient neurological deficit. Chiari I abnormality was also recorded. Subsequent serial imaging of craniocervical region showed the formation of os odontoideum and instability. He became symptomatic from the os odontoideum and the Chiari I abnormality. The patient underwent decompression and intradural procedure for Chiari I abnormality and occipitocervical fusion. Postoperative course was complicated by the failure of fusion and redo. He later required transoral ventral medullary decompression. He recovered.

RESULTS

This is an MR documented craniocervical ligamentous injury with sequential formation of os odontoideum with accompanying changes in the atlas. Despite a subsequent successful dorsal occipitocervical fusion, he became symptomatic requiring transoral decompression.

CONCLUSIONS

Os odontoideum here is recognized as a traumatic origin with the presence of congenital Chiari I abnormality as a separate entity. The changes of the anterior arch of C1 as well as the os formation were serially documented and give credence to blood supply changes in the os and atlas as a result of the trauma. The recognized treatment of dorsal occipitocervical fusion failed in this case requiring also a ventral decompression of the medulla.

[Minimally invasive surgery for invaginated CII odontoid process]

Odontoidectomy is indicated for anterior compression of the brainstem by invaginated odontoid process. This procedure can currently be performed via transoral microsurgical and transnasal endoscopic access.

OBJECTIVE

To analyze the results of endoscopic transnasal odontoidectomy.

MATERIAL AND METHODS

We assessed treatment outcomes in 10 patients with anterior compression of the brainstem by invaginated odontoid process. All patients underwent endoscopic transnasal odontoidectomy.

RESULTS

Brainstem decompression was achieved in all cases.

CONCLUSION

Currently, endoscopic transnasal approach is gradually replacing the transoral one in some patients requiring anterior odontoidectomy. Analysis of literature data reflects the development of this technique taking into account various features of surgical treatment including optimization of dimensions of surgical field, attempts to perform C1-sparing surgeries and analysis of sufficient size of trepanation. Nasopalatine and nasoclival lines are used to select optimal access. Nevertheless, the choice of access depends on equipment of the hospital and surgical experience in most cases.

Neuronavigated Retropharyngeal Anterior Screw Fixation of the Odontoid for the Treatment of C2 Type II Fractures: Case Report

Odontoid fractures, frequently observed in patients over the age of 70, often involve the base of the axis (Anderson-D'Alonzo type 2). For surgical treatment, posterior C1-C2 fixation is the traditional method, whose fusion rates range between 93 and 100%. However, morbidity and mortality rates are high. In addition, cervical motion, especially axial rotation, is postoperatively reduced. Nakanishi and Bohler introduced the anterior screw fixation approach for the surgical treatment of odontoid fracture type II. This procedure preserves the atlantoaxial complex motion, provides immediate stability and high fracture healing rates, and, most importantly, has a low incidence of complications with good fusion rates. The surgical strategy must take into account the patient's anatomy, the morphological characteristics of the fracture, the quality of the bone, and any concomitant injuries. In this chapter, we describe a C2 type II fracture treated via a neuronavigated anterior retropharyngeal approach.

The Impact of C1 Anterior Arch Preservation on Spine Stability After Odontoidectomy: Systematic Review and Meta-Analysis

BACKGROUND

Odontoidectomy for symptomatic irreducible ventral brainstem compression at the craniovertebral junction may result in spine instability requiring subsequent instrumentation. There is no consensus on the importance of C1 anterior arch preservation in prevention of iatrogenic instability. We conducted a systematic review of the impact of C1 anterior arch preservation on postodontoidectomy spine stability.

METHODS

PubMed, Embase, Scopus, Web of Science, and Cochrane were searched following the PRISMA guidelines to include studies of patients undergoing odontoidectomy. Random-effect model meta-analyses were performed to compare spine stability between C1 anterior arch preservation versus removal and posttreatment outcomes between transoral approaches (TOAs) versus endoscopic endonasal approaches (EEAs).

RESULTS

We included 27 studies comprising 462 patients. The most common lesions were basilar invagination (73.3%) and degenerative arthritis (12.6%). Symptoms included myelopathy (72%) and neck pain (43.9%). Odontoidectomy was performed through TOA (56.1%) and EEA corridors (34.4%). The C1 anterior arch was preserved in 16.7% of cases. Postodontoidectomy stabilization was performed in 83.3% patients. Median follow-up was 27 months (range, 0.1-145). Rates of spine instability were significantly lower (P = 0.004) when the C1 anterior arch was preserved. Postoperative clinical improvement and pooled complications were reported in 78.8% and 12.6% of patients, respectively, with no significant differences between TOA and EEA (P = 0.892; P = 0.346). Patients undergoing EEA had significantly higher rates of intraoperative cerebrospinal fluid leaks (P = 0.002).

CONCLUSIONS

Odontoidectomy is safe and effective for treating craniovertebral junction lesions. Preservation of the C1 anterior arch seems to improve maintenance of spine stability. TOA and EEA show comparable outcomes and complication rates.

Factors Associated with Retro-Odontoid Pseudotumor in Long-Term Hemodialysis Patients

OBJECTIVE

Hemodialysis has been reported to be associated with retro-odontoid pseudotumor (ROP), but its clinical characteristics have not been well described. The purpose of the present study was to investigate the factors associated with ROP in hemodialysis patients.

METHODS

A retrospective clinical study of hemodialysis patients was conducted with the evaluation of computed tomography and magnetic resonance imaging of cervical spinal lesions at a single institution from 2012 to 2020. The patients' characteristics and radiographic findings were assessed. A case-control analysis was performed between patients with ROP (ROP group) and patients without ROP (control group).

RESULTS

We analyzed 46 patients. The mean duration of hemodialysis (± standard deviation) was 21.5 ± 11.8 years. The mean retro-odontoid soft tissue thickness was 4.3 ± 0.3 mm and was correlated with the duration of hemodialysis (r = 0.46, P < 0.01). Thirty patients (65.2%) were included in the ROP group. The ROP group showed a significantly longer duration of hemodialysis (24.9 ± 11.2 years vs. 15.2 ± 10.3 years, P < 0.01) and a higher incidence of osteolytic lesions in the atlantoaxial joint compared with the control group (60.0% vs. 18.8%, P < 0.01). Logistic regression analysis revealed the atlantoaxial osteolytic lesions are associated with retro-odontoid pseudotumor in hemodialysis patients (odds ratio, 5.1; 95% confidence interval, 1.1-24.2; P = 0.04).

CONCLUSIONS

The existence of ROP in hemodialysis patients was associated with osteolytic lesions in the atlantoaxial joint. The finding of atlantoaxial erosive lesions in long-term hemodialysis patients requires spine surgeons to carefully evaluate the presence of ROP.

Traumatic lateral atlantoaxial dislocation combined with a type II odontoid fracture in a patient with ankylosing spondylitis: A case report

RATIONALE

Traumatic lateral atlantoaxial dislocation (AAD) combined with an odontoid fracture is extremely rare. The standards applicable to management of the traumatic lateral AAD are still in flux due to the infrequency of this injury.

PATIENT CONCERNS

We present a unique case of traumatic lateral AAD combined with a type II odontoid fracture in a patient with ankylosing spondylitis (AS).

DIAGNOSIS

Spinal computed tomography showed ankylosis of the entire spine from the sacroiliac joint to the cervical spine. On the cervical X-ray the head was rotated to the right with anterior subluxation of the C1 and odontoid tip relative to C2. The coronal computed tomography (CT) scan also revealed left lateral dislocation of C1 on C2 with a horizontal translation of the odontoid tip. On the axial and sagittal CT scan, the left C1 lateral mass was displaced anteriorly and locked by C2 body.

INTERVENTIONS

We performed occipito-cervical fusion (OCF) after successful manual reduction under general anesthesia.

OUTCOMES

The patient's recovery from surgery was uneventful and without complication. At the 3 year follow-up the patient was asymptomatic and reportedly satisfied with the surgery.

LESSONS

Traumatic AAD with an odontoid fracture is an exceedingly uncommon cervical spine injury. A lateral subluxation with a type II odontoid fracture in a patient with AS is rarer still, so much so that this type of subluxation was not classifiable using any of the previously developed classification systems. In this patient with AS, posterior OCF with internal fixation was necessary to avoid hardware failure, particularly in light of the intensive stress caused by AS.

O-Arm Assisted Anterior Odontoid Screw Fixation in Type II and Rostral Type III Odontoid Fractures: Single Center Surgical Series of 50 Patients

BACKGROUND

Accuracy of screw placement is one of the important factors necessary for adequate union in odontoid fractures with malposition rates as high as 27.2% with standard techniques.

OBJECTIVE

To evaluate efficacy of intraoperative O-arm assistance in improving accuracy of anterior odontoid screw placement and clinco-radiological outcome in type II and III odontoid fractures.

MATERIAL AND METHODS

In this retrospective study, surgery consisted of anterior odontoid screw fixation under intraoperative O-arm assistance over 5 years. Demographical, clinical, radiological, operative details and postoperative events were retrieved from hospital database and evaluated for fusion and surgical outcome.

RESULTS

50 patients (Mean age 34.6 years, SD 14.10, range: 7-70 years; 44 males and 6 females) with Type II and Type III odontoid fracture underwent O-arm assisted anterior screw placement. The mean interval between injury and surgery was 12 days (range 1-65 days). Mean operating time was 132.2 min ± SD 33.56 with average blood loss of 93 ml. ±SD 61.46. With our technique, accurate screw placement was achieved in 100% patients. At the mean follow-up of 26.4 month (SD13.75), overall acceptable fusion rate was 97.8% with non-union in 2.2% patients. Morbidity occurred in two patients; one patient developed fixation failure while other patient had nonunion which was managed with posterior C1-C2 arthrodesis. We had surgical mortality in one patient due to SAH. So overall our procedure was successful in 94% patients and among patients whose follow-up was available, acceptable fusion rates of 97.8% were achieved.

CONCLUSION

We conclude that use of intraoperative three-dimensional imaging using O-arm for anterior odontoid screw fixation improves accuracy and leads to improved radiological and clinical outcomes. It further enables us to extend the indications of odontoid screw fixation to selected complex Type II and rostral Type III odontoid fractures.

Single-Stage Posterior Only Approach for Unilateral Atlantoaxial Spondyloptosis with type-II odontoid Fracture in Pediatric Patients

OBJECTIVE

When there is a complete slippage of facet joints of C1 over C2 such that there is no contact between the articulating surfaces of C1 and C2, the condition is known as atlantoaxial spondyloptosis (AAS). AAS represents an extremely rare manifestation of atlantoaxial instability. This study was performed to highlight the presentation, radiological features, and management of unilateral AAS in pediatric patients.

MATERIAL AND METHODS

We retrospectively identified four pediatric patients with AAS from our hospital records in the last 6 years (2014-2019).

RESULTS

Among the four patients with unilateral AAS, three were posttraumic and one was diagnosed with craniovertebral junction tuberculosis (CVJ TB). All the patients had a varying degree of spastic quadriparesis on presentation. One patient with CVJ TB presented with neck tilt. All patients with traumatic unilateral AAS were associated with an odontoid fracture. These patients underwent C1-C2 fixation with complete reduction of spondyloptosis using the techniques of joint manipulation and joint remodeling with a posterior only approach. Complete reduction of AAS in patients with trauma was also associated with the realignment of the odontoid fracture. All patients improved neurologically after surgery and achieved excellent correction of the deformity on a follow-up imaging.

CONCLUSION

Pediatric unilateral AAS is an extremely rare phenomenon. A single-stage posterior approach with C1-C2 fixation is a feasible technique for the treatment of this seemingly difficult to correct deformity in pediatric patients and the clinical outcomes are excellent.

Operative Technique for Resection of a Ventral Trans-Dural Retro-Odontoid Pannus: A 2-Dimensional Operative Video

Retro-odontoid pseudotumors are rare inflammatory complications of atlantoaxial instability often associated with cervical degenerative disease and rheumatoid arthritis. While propagation of these lesions has been shown to cause spinal cord compression and cervical myelopathy, intradural extension has rarely been reported. In this manuscript and two-dimensional illustrative intra-operative video, we demonstrate cervical decompression, removal of the intradural component, and stabilization with C1-2 instrumentation utilizing a posterior approach. A 71 year old patient presented with progressive cervical myelopathy. Preoperative imaging demonstrated a large retro-odontoid pannus causing severe spinal cord compression and an associated contrast-enhancing intradural lesion, in the absence of obvious C1-2 instability or fractures on CT scan. C1-2 posterior decompression and fusion were performed with maximally safe intradural pannus resection and ventral dural reconstruction. Postoperatively, the patient experienced significant improvement in myelopathic symptoms. Imaging demonstrated good spinal cord decompression with complete intradural pannus resection and debulking of the extradural component. Our outcome in this rare complication suggests a posterior approach may be effective in treating similar patients.

Full-Endoscopic Anterior Odontoid Screw Fixation: A Novel Surgical Technique

OBJECTIVE

First, to propose a novel minimally invasive technique of full-endoscopic anterior odontoid fixation (FEAOF) that aims to reduce the risk of retropharyngeal approach (both open and percutaneous techniques) to anterior odontoid screw fixation. Second, to describe steps of the procedure and, lastly, to report the initial outcomes in patients treated with this novel technique.

METHODS

Four non-consecutive patients who were diagnosed with a displaced odontoid fracture (Anderson-D'Alonzo classification type II and Grauer subclassification type A or B) from 2019 to 2020 underwent surgical fixation by our novel technique for anterior odontoid screw fixation. A detailed technical approach of FEAOF for the surgical treatment of type II odontoid fractures was described, and the patients' outcomes based on postoperative radiographic results including computed tomography (CT), clinical outcome parameters including visual analogue scale (VAS) for neck pain both preoperatively and at postoperative follow-up, and range of neck motion at the final follow-up were reported.

RESULTS

The mean age was 33.5 years (24-41), three patients were male. The mean operative time was 93.75 min, and the mean blood loss was 7.5 ml. An immediate post-operative thin-sliced CT showed that all patients achieved satisfactory reduction and proper screw position. No screw malposition or penetration was found. At a 6-month follow-up, a thin-sliced CT demonstrated solid bony union in every case. The mean VAS for neck pain was reduced from 6.5 to 0.6 at the 6-months follow-up. At the final follow-up, all patients showed improvement in ranges of motion without any complications; however, one patient was lost to follow-up.

CONCLUSIONS

FEAOF is a feasible and effective option for treating type II odontoid fractures. The procedure is less invasive than other techniques and provides clear direct visualization of the involved structures.

An Unusual Chordoma of the Odontoid Process: A Case Report and Literature Review

The aim of this study is to present a rare case of chordoma in the odontoid process in which the tumor involved the odontoid process and compressed the spinal cord at the craniocervical junction. We report on the effectiveness and successful outcome of anterior microscopic tumor resection combined with posterior occipitocervical fixation and review the current standard treatment. A 39-year-old man presented with sudden dyspnea and quadriparesis caused by an unknown tumor compression at C2. Radiographic examination revealed a large destructive mass at C2 and heterogeneous enhancement. The patient received urgent surgical intervention by microscopic-assisted anterior tumor resection and posterior spinal fixation from the occiput to the C5 level. The pathohistologic reports for cytokeratins, epithelial membrane antigen, and S-100 protein were positive. The final diagnosis was chordoma of the odontoid process. At the 2-year follow-up, the patient's condition had improved, and a postoperative MRI showed no indication of tumor regrowth. Chordoma of the odontoid process or C2 body is very rare. The current standard management is wide tumor resection to prevent recurrence. The combined approach of anterior tumor resection with microscopic assistance and posterior stabilization of the occiput to C5 is the optimal treatment for this condition.

Management of C2 odontoid peg fragility fractures - A UK survey of spinal surgeons

PURPOSE

Patients sustaining fragility fractures of the C2 odontoid peg have 30-day mortality rates as high as 10% rising up to 34.1% at 1 year. Substantial controversy exists regarding optimal management of these fractures and there is a lack of national guidance to inform best practice. The aim of this study was to determine current practice in the management of these fractures throughout the United Kingdom.

METHODS

A UK wide, cross sectional survey was conducted, asking 10 questions regarding the initial management, imaging and follow-up of an elderly patient with a type 2 fragility odontoid peg fracture. This was publicised through the British Orthopaedic Association website and sent to all members of the Society of British Neurological Surgeons (SBNS) via email.

RESULTS

107 Responses were received. 56% from orthopaedic consultants, 29% from neurosurgical consultants and 15% from senior spine fellows. 86% (92) of respondents choose treatment with a cervical orthosis, with 84% (77) of these opting for a semi rigid Aspen or Philadelphia collar compared to 16% (15) opting for a soft cervical collar. Three (3%) opted for operative intervention with a further three (3%) choosing Halo fixation. Nine respondents (8%) opted for no orthosis and treatment with analgesia alone. Length of immobilisation in cervical orthosis ranged from 6 to 12 weeks. Initial follow-up ranged from 1 week to 6 weeks, with 6% (6) discharged without follow up. There was also marked variation in the use of follow-up imaging with 17% (18) using plain radiographs, 62% (66) requesting lateral flexion / extension radiographs, 10% (11) using CT and 11% (12) not performing any imaging at final follow up. In 60% (64) of cases respondents did not change subsequent management as a result of imaging.

CONCLUSION

Type-2 fragility peg fractures have high morbidity and mortality. There is marked variation in the treatment modalities used, follow-up regime and use of imaging throughout the UK. Given the rapidly increasing incidence of these injuries and the associated mortality this should be a high priority field for further research. Further large scale studies are urgently required to inform best practice and standardise management of these injuries.

Reducible Nonunited Type II Odontoid Fracture with Atlantoaxial Instability: Outcomes of Two Different Fixation Techniques

Displaced nonunited type II odontoid fracture can result in atlantoaxial instability, causing delayed cervical myelopathy. Both Magerl's C1-C2 transarticular screw fixation technique and Harms-Goel C1-C2 screw-rod segmental fixation technique are effective techniques to provide stability. This study aimed to demonstrate the results of two surgical fixation techniques for the treatment of reducible nonunited type II odontoid fracture with atlantoaxial instability. Medical records of patients with reducible nonunited type II odontoid fracture hospitalized for spinal fusion between April 2007 and April 2018 were reviewed. For each patient, specific surgical fixation, either Magerl's C1-C2 transarticular screw fixation technique augmented with supplemental wiring or Harms-Goel C1-C2 screw-rod fixation technique, was performed according to our management protocol. We reported the fusion rate, fusion period, and complications for each technique. Of 21 patients, 10 patients were treated with Magerl's C1-C2 transarticular screw fixation technique augmented with supplemental wiring, and 11 were treated with Harms-Goel C1-C2 screw-rod fixation technique. The bony fusion rate was 100% in both groups. The mean time to fusion was 69.7 (95%CI 53.1, 86.3) days in Magerl's C1-C2 transarticular screw fixation technique and 75.2 (95%CI 51.8, 98.6) days in Harms-Goel C1-C2 screw-rod fixation technique. No severe complications were observed in either group. Displaced reducible, nonunited type II odontoid fracture with cervical myelopathy should be treated by surgery. Both fixation techniques promote bony fusion and provide substantial construct stability.

Odontoid Type II fractures in elderly: what are the real management goals and how to best achieve them? A multicenter European study on functional outcome

Odontoid fractures constitute the most common cervical fractures in elderly. External immobilization is the treatment of choice for Type I and III; there is still no wide consensus about the best management of Type II fractures. Observational multicenter study was conducted on a prospectively built database on elderly patients (> 75 years) with Type II odontoid fracture managed conservatively during the last 10 years. All patients underwent CT scan on admission and at 3 months; if indicated, selected patient had CT scan at 6 and 12 months. All patients were clinically evaluated by Neck Disability Index (NDI), Charlson Comorbidity Index (CCI), and American Society of Anaesthesiologists classification (ASA) on admission; NDI was assessed also at 6 weeks, 3, 6, 12, and 24 months; furthermore, a quality of life (QoL) assessment with the SF-12 form was performed at 3 and 12 months. Among the 260 patients enrolled, 177 (68%) were women and 83 (32%) men, with a median age of 83 years. Patients were followed up for a minimum of 24 months: 247 (95%) showed an excellent functional outcome within 6 weeks, among them 117 (45%) showed a good bony healing, whereas 130 (50%) healed in pseudo-arthrosis. The residual 5% were still variably symptomatic at 12 weeks; however, only 5 out of 13 (2% of the total cohort) required delayed surgery. This study showed that a conservative approach to odontoid Type II fracture in elderly is an effective and valid option, resulting in an excellent functional outcome (regardless of bony fusion) in the majority of cases. Failure of conservative treatment can be safely addressed with surgical fixation at a later stage.

Retro-Odontoid Pseudotumor Without Radiographic Instability with Congenital C1 Assimilation and C2-C3 Fusion: A Case Report

CASE

The authors present a case of retro-odontoid pseudotumor (ROP) with congenital C1 assimilation and C2-C3 block vertebra without radiological instability who presented with cervical myelopathy with spastic quadriparesis. The patient was managed with occipitocervical fusion and C1 laminectomy. She had rapid neurological recovery in 3 months postoperatively and at 2 years had complete resolution of the retro-odontoid mass.

CONCLUSION

C1 assimilation without apparent radiographic instability as a cause of ROP is underappreciated. This case report and review of literature highlight that C1 assimilation and C2-C3 fusion can lead to ROP even in the absence of apparent radiographic instability with posterior atlantoaxial fusion alone providing good results.

Anterior Odontoid Screw Fixation for C2 Fractures: Surgical Nuances, Complications, and Factors Affecting Fracture Union

OBJECTIVE

Type II odontoid fractures are the commonest C2 fractures. The management of dens fractures remains controversial with various radiological and fracture morphological factors affecting the approach and outcomes.

METHODS

All cases of anterior odontoid screw fixation between 2010 and 2020 were retrospectively analyzed. Patients' clinical, radiological (type of fracture, orientation, displacement, and diastasis), operative (single vs. double screw) and follow-up records were documented. The postoperative imaging findings were classified into grades I (excellent), II (good), and III (poor) based on the anatomical alignment with the screw. Follow-up cervical computed tomography was reviewed for fracture union.

RESULTS

A total of 49 patients with a mean age of 37.3 ± 13.8 years were included in the study. The average time from injury to surgery was 23.1 ± 22.2 days. The bicortical screw purchase and superoposterior odontoid tip breach significantly affected the postoperative alignment (P = 0.035 each). Fracture union was noted in 41 (83.7%) patients. The horizontal fracture displacement ≥2.5 mm (P = 0.02) and poor postoperative fracture alignment (P < 0.001) resulted in worse fracture union rates. Transient dysphagia was the commonest complication (n = 12), whereas screw breakout (n = 2) and pullout (n = 2) were other hardware-related complications. One patient underwent re-exploration for screw readjustment and 2 underwent posterior instrumentation.

CONCLUSIONS

Anterior odontoid screw fixation is technically straightforward, less morbid, and preserves biomechanical cervical mobility, when compared with the posterior instrumentation. With careful patient selection, meticulous surgical planning, and intraoperative image-guided screw insertion, good fracture union outcomes can be obtained. In the current study, we were able to achieve stable fracture union in 83.7% patients.

Institutional review of the management of type II odontoid fractures: associations and outcomes with fibrous union

OBJECTIVE

Type II odontoid fractures may be managed operatively or nonoperatively. If managed with bracing, bony union may never occur despite stability. This phenomenon is termed fibrous union. The authors aimed to determine associations with stable fibrous union and compare the morbidity of patients managed operatively and nonoperatively.

METHODS

The authors performed a retrospective review of their spine trauma database for adults with type II odontoid fractures between 2015 and 2019. Two-sample t-tests and Fisher's exact tests identified associations with follow-up stability and were used to compare operative and nonoperative outcomes. Sensitivity, specificity, and predictive values were calculated to validate initial stable upright cervical radiographs related to follow-up stability.

RESULTS

Among 88 patients, 10% received upfront surgical fixation, and 90% were managed nonoperatively, of whom 22% had fracture instability on follow-up. Associations with instability after nonoperative management include myelopathy (OR 0.04, 95% CI 0.0-0.92), cerebrovascular disease (OR 0.23, 95% CI 0.06-1.0), and dens displacement ≥ 2 mm (OR 0.29, 95% CI 0.07-1.0). Advanced age was not associated with follow-up instability. Initial stability on upright radiographs was associated with stability on follow-up (OR 4.29, 95% CI 1.0-18) with excellent sensitivity and positive predictive value (sensitivity 89%, specificity 35%, positive predictive value 83%, and negative predictive value 46%). The overall complication rate and respiratory failure requiring ventilation on individual complication analysis were more common in operatively managed patients (33% vs 3%, respectively; p = 0.007), even though they were generally younger and healthier than those managed nonoperatively. Operative or nonoperative management conferred no difference in length of hospital or ICU stay, discharge disposition, or mortality.

CONCLUSIONS

The authors delineate the validity of upright cervical radiographs on presentation in association with follow-up stability in type II odontoid fractures. In their experience, factors associated with instability included cervical myelopathy, cerebrovascular disease, and fracture displacement but not increased age. Operatively managed patients had higher complication rates than those managed without surgery. Fibrous union, which can occur with nonoperative management, provided adequate stability.

PICA injury secondary to anterior odontoid screw fixation: Case report of an exceptional complication

BACKGROUND

Odontoid fracture is a common injury in the upper cervical spine that can sometimes be managed by anterior odontoid screw fixation.

CASE DESCRIPTION

We report the first case of iatrogenic postero-inferior cerebellar artery (PICA) injury while performing anterior odontoid screw fixation for a type II odontoid fracture in a 22-year-old man. Fisher grade 4 subarachnoid hemorrhage secondary to iatrogenic pseudoaneurysm formation was managed by the endovascular neuroradiologist. Odontoid fracture was then managed posteriorly using Harm's technique. Postoperative 12-month follow-up revealed good clinical and radiological results. CT scan showed fusion. Complete exclusion of the pseudo aneurysm with a mild stroke in the inferior left cerebellar hemisphere were noted on the MRI. There were no cerebellar ataxia or swallowing disorders.

CONCLUSION

To the best of our knowledge, this is the first case report of iatrogenic PICA injury in anterior odontoid screw fixation. The patient was well managed in our institution within a multidisciplinary team. We recommend that surgical management of odontoid fractures should be performed in expert centres.

Experience in surgical treatment of type Ⅱ odontoid fractures: A report of two cases and review of the literature

Two cases of type Ⅱ odontoid fractures were reported to share our experience in surgery treatment of such cases. A 33-year-old woman with comminuted type Ⅱ odontoid fracture and a 42-year-old man with fracture end hardened type Ⅱ odontoid fracture received surgical treatment in our hospital. Though imaging examination suggested that these two patients were suitable for anterior screw fixation, we encountered difficulties during the operation. The two patients eventually underwent posterior C1-C2 fusion surgery and recovered well. According to the experience of these two cases, we found that the fracture line angle and the degree of comminution are two important factors affecting surgical decision-making. Although anterior screw fixation is the ideal choice for type Ⅱ odontoid fractures with anterior superior to posterior inferior fracture line, it may not be the best choice for comminuted or fracture end hardened type Ⅱ odontoid fractures.

[Os odontoideum. Presentation in adult age]

The Os odontoideum is a variable oval or round ossicle with a smooth cortical border, which partially corresponds to the odontoid process, without having continuity with the rest of C2 bone. The multifactorial etiology causes instability and clinically translates into pain and compression data into neural structures. The treatment of choice is surgical and techniques have been developed that focus on preserving the stability of the segment. We present the case of a 23-year-old female patient, who begins to suffer at 8 years of age, refers to moderate to severe cervicalgia, which develops with paresthesias in the left hemisphere and later paresis of the left thoracic limb. Physical examination showed hypoaesthesia of the left hemisphere, as well as paresis of the left thoracic limb. Extension studies demonstrate chronic axonal lesion from C1 to C3, predominantly left, imaging studies showing axial instability and magnetic resonance bulbar compression. The patient receives surgical treatment consisting of posterior fixation C1-C2, evolving satisfactorily.

Endoscopically-Assisted Percutaneous Unilateral Atlantoaxial Screw-Rod Nonfusion Fixation Treatment for Type II Odontoid Fractures in Geriatric Patients: Case Series and Technical Note

BACKGROUND

Considerable controversy exists regarding the optimal treatment for type II odontoid fractures in geriatric patients. Surgical intervention can help patients return to their prior level of function as rapidly as possible while avoiding the morbidity and mortality associated with prolonged and bedbound hospitalization. However, the optimal treatment is still a difficult choice for patients with increased risk from anesthesia.

OBJECTIVES

The objective of our study was to describe an innovative method of endoscopically-assisted percutaneous unilateral C1 lateral mass screw and C2 pedicle screw-rod nonfusion fixation for type II odontoid fractures in geriatric patients.

STUDY DESIGN

A case series design and technical notes.

SETTING

This study took place at Second Affiliated Hospital of Chongqing Medical University.

METHODS

Seven geriatric patients (> 65 years) with type II odontoid fractures and an American Society of Anesthesiologists (ASA) score of 2 or higher received endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation. After surgery, all patients were required to wear a rigid collar full-time for 12 weeks. Intraoperative data, the bone union time, American Spinal Injury Association (ASIA) scale scores, Neck Disability Index (NDI) scores, and postoperative complications were collected for assessment.RESULTS The surgical goal was successfully achieved in all patients, 3 of whom had high ASA scores (>= 3) and underwent surgery under local anesthesia. The operative time ranged from 112 to 169 minutes (mean, 131.1 minutes). No neurovascular complications were observed intraoperatively or postoperatively. All patients rapidly returned to their prior level of function and were followed up for 12 to 24 months (average: 16.9 months). Bone union was achieved in all patients.

LIMITATIONS

This study is limited by being a retrospective study.

CONCLUSIONS

Endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation is a feasible technique for type II odontoid fractures in geriatric patients. This method offers a compromise between non-operative and operative treatment and allows geriatric patients to rapidly return to their prior level of function.

KEY WORDS

Endoscopically-assisted surgery; geriatric patient; percutaneous atlantoaxial fixation; type II odontoid fracture; unilateral nonfusion fixation.

[Untreated os odontoideum may cause tetraplegia]

This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to management of the disease. Surgery of symptomatic patients is advocated, as there is more uncertainty about the treatment of asymptomatic patients. Diagnosis is obtained with plain X-ray. However, nowadays MRI and CT scanning are recommended for further clarification and judgement of the severity. Knowledge of OO is important to minimise misjudgement and consequently inappropriate treatment. It is recommended, that patients are examined by highly specialised spine doctors before further cervical manipulation due to the high risk of instability with potentially severe consequences.