Comparison of the far lateral and extreme lateral variants of the atlanto-occipital transarticular approach to anterior extradural lesions of the craniovertebral junction

OBJECTIVE: Managing lesions situated in the anterior aspect of the craniovertebral junction (CVJ) remains a challenging neurosurgical problem. The purposes of this study were to examine the microsurgical anatomy of the anterior extradural aspect of the CVJ and the differences in the exposure obtained by the far lateral and extreme lateral atlanto-occipital transarticular approaches. The far lateral approach, as originally described, is a lateral suboccipital approach directed behind the sternocleidomastoid muscle and the vertebral artery and just medial to the occipital and atlantal condyles and the atlanto-occipital joint. The extreme lateral approach, as originally described, is a direct lateral approach deep to the anterior part of the sternocleidomastoid muscle and behind the internal jugular vein along the front of the vertebral artery. Both approaches permit drilling of the condyles at the atlanto-occipital joint but provide a different exposure because of the differences in the direction of the approach. METHODS: Fifteen adult cadaveric specimens were studied using a magnification of x3 to x40 after perfusion of the arteries and veins with colored silicone. The microsurgical anatomy of the extradural aspects of the CVJ and the two atlanto-occipital transarticular approaches were examined in stepwise dissections. RESULTS: The far lateral atlanto-occipital transarticular approach provides excellent exposure of the extradural lesions located in the ipsilateral anterior and anterolateral aspects of the extradural region of the CVJ. The extreme lateral atlanto-occipital transarticular approach provides excellent exposure, not only on the side of the exposure, but also extending across the midline to the medial aspect of the contralateral atlanto-occipital joint and the lower clivus. CONCLUSION: The far lateral and extreme lateral variants of the atlanto-occipital transarticular approach provide an alternative to the transoral approach to the anterior extradural structures at the CVJ. Compared with the transoral approach, both approaches provide a shorter operative route, avoid the contaminated nasopharynx, reduce the incidence of cerebrospinal fluid leak, and are not limited laterally by the atlanto-occipital joint.     

内镜辅助经高颈前咽后入路治疗颅颈交界区脊椎病变

目的 探讨内镜辅助下经高位颈前咽后入路治疗颅颈交界区脊椎病变的可行性和临床疗效.方法 2007年4月至2009年10月,治疗19例颅颈交界区脊椎病变患者,男9例,女10例;年龄16～62岁,平均41.6岁;陈旧性齿突骨折合并脱位5例,单纯寰椎脱位2例,游离齿突6例,Marfan综合征1例,Kippel-Feil综合征合并颅底凹陷1例,枢椎肿瘤3例,寰枢关节类风湿关节炎1例.均采用内镜辅助下经高位颈前咽后人路完成前路手术操作,其中8例行寰枢关节前路松解复位,8例行齿突切除减压,3例行肿瘤全切与重建.同时一期行后路固定植骨融合术,其中13例采用寰枢椎椎弓根钉固定融合,4例行枕颈融合,2例行C1～C3椎弓根固定融合.结果 8例复位患者均获得解剖复位,8例齿突切除患者行部分或全部齿突切除,3例肿瘤病灶均完全切除.随访6～36个月,平均14个月,全部病例均获骨性融合.14例术前有脊髓症状者末次随访时日本矫形外科学会(Japanese Orthopaedic Association,JOA)评分从术前(9.1±3.3)分提高到术后(14.1±2.9)分JOA改善率优7例,良5例,可1例,差1例.术中出现硬膜破裂1例,经生物蛋白凝胶封堵及术后腰椎蛛网膜下腔置管引流1周后治愈;术后出现吞咽障碍3例,均静脉应用地塞米松及甘露醇,术后3个月内均恢复正常.末次随访时,无一例患者发生感染及内固定松动.结论 内镜辅助经高位颈前咽后入路是治疗颅颈交界区病变的安全、有效、微创的方法.

Abstract：

Objective To assess the feasibility and clinical results of video-assisted high anterior transcervical approach (Smith-Robinson) in treatment of spinal lesions of the craniovertebral junction. Methods Between April 2007 to October 2009, nineteen consecutive patients with spinal lesions of the craniovertebral junction were included in the study. There were 9 males and 10 females aged from 16 to 62 years old with a mean of 32 years. The primary pathologies included 4 cases with chronic odontiod fracture, 2 cases with purely irreducible atlantoaxial dislocation, 6 cases with os odonteideum, 1 case with Marfan synd rome, 1 case with primary basilar invagination from Kippel-Feil syndrome, 3 case with axis tumor and 1 case with irreducible rheumatoid atlantoaxial dislocation. All of the patients underwent combined video-assisted high anterior transcervical procedure and posterior fixation at one-stage. The anterior procedure included atlantoaxil release and reduction (8 cases), odontoidectomy (8 cases), and intralesional extracapsular excision and reconstruction (3 tumor cases). The posterior technique were C1-C2 pedicle screw fixation (13 cases), C1-C3 pedicle screw fixation (2 cases), and occipitalcervical fusion (4 cases). Results Anatomical reduction was achieved in eight cases with anterior release and reduction. Tumors were completely removed in three cases with axial tumor. The mean follow-up was 14 months (6-36 months). All of them achieved solid bone fusion. In the 14 patients with symptoms of spinal cord dysfunction, the average Japanese Orthopaedic Association (JOA)score had improved from 9.1±3.3 preoperatively to 14.1±2.9 postperatively. The improvement rate was excellent for 7 cases, good for 5 cases, fair for lcase and poor for 1 case. One patient experienced leakage of cerebrospinal fluid which was resolved by bioprotein gelatin blocking and lumbar subarachnoid continuous drainage within 1 week. Dysphagia which occurred in 3 cases responded well to dexamethason and mannitol.No infection and hardware failure were observed. Conclusion Video-assisted high anterior transcervical procedure is a safe and effective alternative for treating spinal lesions in the craniovertebral junction.     

经口前路寰枢椎复位钢板系统治疗先天性枕颈交界区畸形

目的探讨经口前路寰枢椎复位钢板（transoral atlantoaxial reduction plate,TARP）系统用于先天性枕颈交界区畸形手术治疗的临床疗效。方法 2007年12月-2011年12月采用TARP系统治疗先天性枕颈交界区畸形患者35例。所有患者术前术后均行颈椎过伸过屈位X线、枕颈交界区CT扫描及MRI以评估局部畸形及颈脊髓腹侧压迫情况;采用日本骨科学会（Japanese Orthopaedic Association,JOA）评分（17分法）评估术前术后脊髓损伤及恢复情况。术后3、6、12个月复查颈椎正侧位X线片及CT,评价内固定效果及融合情况。结果 35例患者均顺利完成手术,术后MRI示颈脊髓腹侧压迫均有明显减轻,延髓脊髓角术后平均增加约29.7°,31例（89%）患者术后神经功能有明显改善,4例术前术后神经功能无变化。术后随访1年未发现寰枢椎再脱位、螺钉松动、断裂或移位等并发症。结论TARP系统可对先天性枕颈交界区畸形合并腹侧颈脊髓压迫进行一期减压、复位及内固定,是枕颈交界区畸形理想的治疗手段之一。     

Transoral approach to extradural lesions of the lower clivus and upper cervical spine: an experience of 19 cases

An experience with 19 cases of transoral exposure of the lower clivus and ventral aspect of the upper cervical spine is presented. The spectrum of pathological entities in this series includes malformative, neoplastic, and spondylotic conditions. The report is designed to focus upon some points of overall surgical management of patients treated by the transoral approach, with emphasis on management of postoperative instability, and to underline the discrepancy in the prognosis of congenital and acquired disorders, in terms of mortality, morbidity, and long-term results.     

Endoscope-assisted microsurgical transoral approach to the anterior craniovertebral junction compressive pathologies

At the present time, an update to the classical microsurgical transoral decompression is strongly provided by the most recent literature dealing with the introduction of the endoscopy in spine surgery. In this paper, we present our experience on the endoscope-assisted microsurgical transoral approach to anterior craniovertebral junction (CVJ) compressive pathology. We analysed seven patients (3 paediatrics and 4 adults ranging from 6 to 78 years) operated on for CVJ decompressive procedures using an open access, microsurgical technique, neuronavigation and endoscopy. All techniques mentioned were simultaneously employed. Among the endoscopic routes described in the literature, we have preferred the transoral using 30° endoscopes. In all the cases endoscopy allowed a radical decompression compared to the microsurgical technique alone, as confirmed intraoperatively with contrast medium fluoroscopy. In conclusion, endoscopy represents a useful complement to the standard microsurgical approach to the anterior CVJ; it provides information for a better decompression with no need for soft palate splitting, hard palate resection, or extended maxillotomy. Moreover, intraoperative fluoroscopy helps to recognize residual compression. Virtually, in normal anatomic conditions, no surgical limitations exist for endoscopically assisted transoral approach, compared with the pure endonasal and transcervical endoscopic approaches. In our opinion, the endoscope deserves a role as “support” to the standard transoral microsurgical approach since 30° angulated endoscopy significantly increases the surgical area exposed at the level of the anterior CVJ.     

Endoscopic far-lateral approach to the posterolateral craniovertebral junction: an anatomical study

Minimally invasive surgery to the posterolateral craniovertebral junction (CVJ) has not been sufficiently described. The aims of this study were to evaluate the feasibility of an endoscopic far-lateral approach to the posterolateral craniocervical junction and to better understand the related anatomy under distorted endoscopic view. Ten fresh cadavers were studied with 4-mm 0° and 30° endoscopes to develop the surgical approach and to identify surgical landmarks. After making a 3-cm straight incision behind the mastoid process, the superior oblique and rectus capitis posterior major muscles were partially exposed. An endoscope was then introduced and the two muscles were followed inferiorly until the posterior arch of the atlas appeared. The two muscles were removed to create ample working space without violating the posterior atlanto-occipital membrane. The vertebral artery was identified by the landmark of the posterior arch of the atlas, and the atlanto-occipital joint and foramen magnum were exposed. In addition to suboccipital craniectomy, transcondylar, supracondylar, and paracondylar extension by drilling were applicable through the narrow corridor under superb visualization. The intradural neurovascular structures from the acousticofacial bundle to the dorsal root of C2, anterolateral space of the foramen magnum, cerebellomedullary fissure, and fourth ventricle were clearly demonstrated. This endoscopic far-lateral approach offers excellent exposure of surgical landmarks around the posterolateral CVJ with minimal invasiveness. Endoscopic soft tissue dissection is key to creating the surgical corridor. This approach could offer an alternative to the conventional far-lateral approach in selected cases.     

The transoral approach for the management of intradural lesions at the craniovertebral junction: review of 7 cases

The main difficulty in dealing with intradural lesions located ventrally in the region of the craniovertebral junction (CVJ) is related to their relative inaccessibility. Posterolateral approaches involve some manipulation of the brain stem and provide limited access because of the necessity of working between the cranial nerves. Even then, the view of the ventral midline and across is limited. The transoral approach, which has been widely used for the management of extradural lesions in this area, is also useful for the treatment of intradural lesions. It provides an unimpeded although somewhat restricted, view of the ventral aspect of the CVJ without the need for brain retraction. The cranial nerves and vertebral arteries are not interposed between the surgeon and the lesion. The risks of cerebrospinal fluid leakage and infection are greatly diminished by the use of fibrin adhesive and prolonged diversion of the cerebrospinal fluid. The use of this approach, together with its technical difficulties and results, in the management of seven purely intradural lesions located ventrally at the CVJ, is discussed.     

Atlantoaxial dislocation associated with a mass in the extradural craniovertebral junction unrelated to rheumatoid arthritis. Case report

A 61-year-old woman without rheumatoid arthritis (RA) was admitted with atlantoaxial dislocation (AAD) and a retroodontoid mass at the craniovertebral junction manifesting as a 1-year history of numbness and mild weakness of the right upper extremity. Computed tomography and magnetic resonance (MR) imaging showed AAD and a mass at the craniovertebral junction. She had no past history of RA or trauma in the head and neck. She underwent surgery to obtain the histological diagnosis of the mass and to improve AAD-induced instability. The lesion was approached through the right transcondylar fossa approach with C-1 laminectomy. Intraoperative pathological examination showed cicatrizing collagen fibers and no obvious tumor cells. After partial removal of the lesion, the AAD was fixed with the posterior approach. The symptoms subsided soon after surgery and the mass decreased on MR images taken 3 months after surgery. If a pseudotumor is suspected based on the preoperative radiological investigation in a non-RA patient with AAD and the symptoms are not progressive, stabilization can be expected to induce spontaneous regression without urgent direct excision of the mass.     

Tuberculosis of the craniovertebral junction

Purpose

Tuberculosis (TB) of craniovertebral junction (CVJ) occurs in 1–5 % of cases of TB spondylitis. This can be a life-threatening condition due to mass effect of infective process or resultant instability. Surgical indications for TB of CVJ are not clear from literature.

Methods

We have reviewed all the patients with TB of CVJ admitted at our center between 2005 and 2010.

Results

There were 15 patients including 10 males and 5 females. Average age was 38 years and average duration of symptoms was 8 months. All patients were started on multidrug antituberculous chemotherapy and skull traction. Those patients who failed to respond in 4–6 weeks and had persistent instability or neurological deficit were offered surgery. Rest was treated conservatively by immobilisation or traction. All five patients who were surgically treated had occipitocervical fusion (OCF) with titanium screws and plate/rod construct combined with posterior decompression if needed. Only one patient needed anterior surgery in addition to OCF at a later stage. All patients improved neurologically whether they were treated surgically or conservatively. Only difference was that surgically treated patients had earlier pain relief, mobilisation, neurological improvement and lesser complications.

Conclusion

We recommend that all patients with TB of CVJ with instability and neurological compromise, who fail to respond to 4–6 weeks of antituberculous chemotherapy and skull traction should be offered occipitocervical fusion with or without posterior decompression. Anterior surgery will be needed only in those few cases who do not improve neurologically after OCF.

     

Infantile myofibromatosis of the craniovertebral junction

Infantile myofibromatosis (IM) is a rare pathological entity characterized by solitary or multiple nodular skin, soft tissues or bony lesions. Craniovertebral (CV) junction lesions are rare. We report the successful management of a solitary IM involving the posterior elements of the CV junction in a 6-month-old child.     

Management of craniovertebral junction tuberculosis

BACKGROUND: Tuberculosis of the craniovertebral junction (CVJ) is extremely rare. However, recent evidence suggests that the incidence of this condition may be increasing. The diagnosis is often difficult despite advances in imaging using magnetic resonance imaging. The transoral approach to the anterior CVJ provides excellent access to this region, has low mortality and morbidity, and enables biopsy of lesions and decompression of the neuraxis. Management of associated atlantoaxial instability, with regard to timing and method of stabilization, is controversial. METHODS: We report 24 cases of CVJ tuberculosis. Prominent manifestations of the disease included neck pain and stiffness, swelling of the retropharyngeal soft tissues, quadriparesis, osteolytic erosions, and atlantoaxial subluxation. Seven patients had acute presentation. All patients received antituberculous drug treatment for 18 months. Four patients were managed conservatively, 5 underwent only transoral biopsy, 9 patients underwent transoral decompression and posterior fusion, and 6 patients underwent only posterior fusion. RESULTS: Histopathologic analysis of biopsy material revealed abscess only in 5 cases, granulation tissue only in 6, abscess with granulation tissue in 4, granulation tissue with chronic osteomyelitis in 5, and chronic inflammation in 2. All patients improved, with mean improvement in Nurick grading of 1.71. Even patients with spinal cord signal intensity changes on magnetic resonance images showed improvement. CONCLUSIONS: Although CVJ tuberculosis is a rare disease, the outcome of treatment is good. Antituberculous drug therapy remains the mainstay of treatment after confirming the diagnosis. The surgical management options include transoral decompression with or without posterior fusion, depending upon the presence and persistence of atlantoaxial instability.     

Synovial cyst at the craniovertebral junction

A case of synovial cyst of the upper cervical spine that resulted in spastic quadriparesis and sensory loss is reported. Radiographic evaluation included a computed tomography scan after myelography and a magnetic resonance imaging scan. The synovial cyst was removed by a laminectomy at C-1 and C-2, combined with a foramen magnum craniectomy. The patient had a good recovery.     

Management of tuberculomas of the craniovertebral junction

Tuberculosis of the craniovertebral junction is extremely rare. However, recent evidence suggests that the incidence of this condition may be increasing in the United Kingdom. The diagnosis is often difficult despite advances in imaging using MRI. CT guided biopsy of lesions often yields inconclusive results. The transoral approach to the anterior craniovertebral junction provides excellent access to this region with a low operative morbidity and mortality, enabling biopsy of lesions and decompression of the neuraxis. Management of secondary atlantoaxial instability, regarding both timing and method of stabilization, is controversial. We report two cases of tuberculomas of the craniovertebral junction, that illustrate the role of transoral surgery in both diagnosis and treatment of this condition. Previous management strategies are reviewed and future recommendations are presented.