Extended transoral approaches: surgical technique and analysis.
ABSTRACT The transoral approach provides the most direct exposure to extradural lesions of the ventral craniovertebral junction. Lesions that extend beyond the exposure provided by the standard transoral approach require an extended transoral modification. The exposure can be expanded in the sagittal and axial planes by adding mandibulotomy, mandibuloglossotomy, palatotomy, and transmaxillary approaches to the standard transoral approach. Extended transoral approaches increase the surgical complexity and the risk of cosmetic and functional complications. Until recently, selection of an extended approach has been arbitrary and dependent on the surgeon's familiarity with the surgical approach.
We review the literature of extended transoral approaches and analyze the different modifications in terms of the technical aspects, added exposure, and complications.
Classic approaches and recently published morphometric studies that objectively document the gain in exposure provided by several modifications were analyzed and tabulated to outline the limits of exposure and risk of complications associated with the various modifications.
Transmaxillary approaches expand the exposure to include the sphenoid sinus and upper lateral clivus. To expand the exposure more inferiorly to C4-C5, mandibulotomy or mandibuloglossotomy can be applied. Mandibuloglossotomy increases the rostral exposure as well to the upper third of the clivus. Palatotomy increases rostral exposure without requiring a facial incision or perioperative tracheostomy, but is associated with a significant risk of velopharyngeal insufficiency.
Surgical decisions can be based on comprehensive preoperative evaluation of anatomy, pathology, and radiographic studies to maximize exposure while minimizing complications.
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ABSTRACT: STUDY DESIGN:: A retrospective study of consecutive patient series. OBJECTIVES:: To report a technique of odontoidectomy using a transoccipitocervical posterolateral approach for occipitoatlantoaxial ventral lesions in a long-term follow-up study. SUMMARY OF BACKGROUND DATA:: Occipitoatlantoaxial malformation and old traumatic dislocation usually cause compression of the high cervical spinal cord from a variety of different directions and angles, leading to high morbidity. The main objective of treatment is to relieve the anteroposterior compression and to restore the stability of the occipitocervical region. Currently, there are 2 approaches to perform the surgical procedure: (1) posterior decompression by suboccipital and occipitocervical fusion and internal fixation; and (2) decompression by a transoral approach to an odontoid resection. However, there are some short points, which need to be changed, such as the incomplete decompression (the former), narrow view, cerebrospinal fluid leakage, and the high infection rates. METHODS:: From 1999 to 2006, 23 patients with occipitoatlantoaxial ventral lesions were treated using a transoccipitocervical posterolateral approach for decompression. The procedure included an expansion of the foramen magnum, a resection of the posterior arch of atlas, a lateral occipitocervical epidural exposure to the odontoid and the C2 vertebra, and an excision of the odontoid. Thus, an anteroposterior decompression and occipitocervical spinal fusion was achieved. Neurological function, daily living ability, and the work ability of patients were assessed in a follow-up study. RESULTS:: A 28-year-old woman died of respiratory and circulatory failure 10 hours after operation. The remaining patients survived without postoperative infection. The neurological injury in 17 patients did not deteriorate, whereas 5 patients had decreased sensation in the upper limbs, and the elbow flexor muscle strength in 2 patients declined by 1 grade on the operation side. Short-term follow-up (3-6 mo, 22 cases) indicated that 19 patients recovered normal sensation with decreased limb muscle tension. Motor function was improved by >1 grade (5 patients with postoperative nerve injury recovered to preoperative levels or better). Long-term follow-up (>4 y) of 15 patients (10 patients by clinic visit and 5 patients by correspondence) indicated that the occipitoatlantoaxial regions were stable without local discomfort or loss of nerve function. Fourteen patients were able to care for themselves and some patients regained their ability to work. One patient felt no significant improvement after surgery and had no improvement in the quality of life. CONCLUSIONS:: Transoccipitocervical posterolateral approach to occipitoatlantoaxial ventral lesions provides a broad and sterile operating field to perform anteroposterior decompression and occipitocervical spinal fusion simultaneously. Neurological improvement is significant, and the long-term follow-up results are satisfactory.Journal of spinal disorders & techniques 12/2011; DOI:10.1097/BSD.0b013e31823faec4 · 1.21 Impact Factor
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ABSTRACT: Three endoscopic anterior approaches, the transnasal, transoral, and transcervical approaches, are used for ventral lesions of the craniovertebral junction and have been compared regarding surgical working distances and approach angles. However, how the position of the cervical spine influences the depths of surgical corridors and approach angles for the three approaches has not been evaluated. To evaluate the depths of surgical corridors and the approach angles for the three endoscopic approaches, taking the influence of cervical spine position into account. A radiographic study comparing three anterior endoscopic approaches to the craniovertebral junction. Cervical extension and flexion radiographs for 34 patients and cross-sectional computed tomography scans for 30 additional patients were assessed. The depths of the surgical corridors and the approach angles for the three endoscopic approaches in the midsagittal planes. We determined the mean angles of the surgical trajectories for the endoscopic transoral and transcervical approaches on cervical extension and flexion radiographs. In addition, we measured the depths of the surgical corridors and the approach angles for the three approaches in the midsagittal plane. The average depths of surgical corridors were as follows: endonasal, 93.65 mm; transoral, 85.27 mm; transcervical, 62.97 mm (in extension). The average approach angles were as follows: endonasal, 31.22°; transoral, 30.87°; transcervical, 36.58° (in extension). The position of the cervical spine does not influence the surgical convenience of the endoscopic transnasal approach, but it can influence the endoscopic transoral and transcervical approaches, especially the latter. The endoscopic transcervical approach offers several advantages over the endoscopic transoral and endonasal approaches.The spine journal: official journal of the North American Spine Society 10/2013; 14(1). DOI:10.1016/j.spinee.2013.06.079 · 2.90 Impact Factor
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ABSTRACT: BACKGROUND: The proatlas is derived from the fourth occipital sclerotome in human embryos. It usually fuses with the three upper occipital sclerotomes to form the occipital bone. However, this does not always occur. Manifestations of a partial proatlas structure may persist due to failure of fusion. CLINICAL CONSIDERATIONS: These embryological remnants can induce several symptoms in humans, ranging from mild to severe. On occasion, this structure can go unnoticed until a precipitating traumatic event results in symptoms. Proatlas segmentation abnormalities form bony masses at C1 and the foramen magnum. A number of surgical procedures have been devised to rectify the resulting neural compression and vascular compromise. DISCUSSION: This paper will discuss the development of the proatlas and the resultant anomalies associated with its failure to merge with the occipital sclerotomes to form the occipital bone. In addition, some consideration of comparative anatomy and surgical techniques will be presented.Child s Nervous System 03/2012; 28(3):349-56. DOI:10.1007/s00381-012-1698-8 · 1.24 Impact Factor