SpineTransthoracic discectomy without interbody fusion
Introduction
Herniated thoracic disks are rare entities and their surgical treatment comprises 0.15% to 4% of all disk operations [2], [3], [8], [10], [13], [16], [19], [21], [23]. Surgical approaches have included pediculectomy, costotransversectomy, lateral extracavitary, transthoracic thoracotomy, and thoracoscopy. The factors that determine the surgical approach include disk size, location, extent of calcification, surgeon experience, degree of spinal cord deformation, and the medical condition of the patient [22].
For patients who undergo anterior procedures such as transthoracic discectomy, some authors recommend interbody fusion for the presumed risk of postoperative progressive kyphotic deformity, axial spine pain, and neurological deterioration [5], [7], [12], [15]. The authors of the present study have analyzed the clinical and radiological outcomes of a consecutive series of patients who underwent transthoracic discectomy without interbody fusion. To the authors' knowledge, there has been no clinical series directly addressing the important question regarding the need for interbody arthrodesis after transthoracic discectomy.
Section snippets
Patient population
Eighteen consecutive patients underwent transthoracic discectomy without interbody fusion by a single neurosurgeon (WEK) at Mayo Clinic (Rochester, MN) between 1996 and 2002. The Mayo Clinic Investigational Review Board approved this study and all patients gave consent regarding their participation. There were 11 women and 7 men with a mean age of 54 years (range, 28-84 years). All patients underwent a complete preoperative neurological evaluation by a staff neurologist and a preoperative
Surgical technique
A thoracic surgeon performed the exposure in all cases. The ipsilateral rib head abutting the affected disk was removed to expose the disk. The neuroforamen superior and inferior to the disk was exposed. The ipsilateral pedicle immediately below the affected disk space was partially resected using a high-speed drill, and the posterolateral portions of the vertebral bodies above and below the disk space were drilled to expose the disk herniation (Fig. 2, Fig. 3). Using a flat probe and disk
Results
Of our 18 patients, 15 were available for a telephone survey with a mean follow-up of 28 ± 20 (SD) months. Preoperative and postoperative x-ray radiographs were available for comparison for 16 patients with a mean follow-up of 22 ± 24 (SD) months.
Clinically, 15/18 patients (83%) demonstrated improvement in their preoperative symptoms and signs; 2 patients were unchanged (11%) and 1 patient suffered from a worsening of her gait (6%). No patient had a new onset of axial spine pain. The 2 patients
Discussion
The aim of this study was to determine the safety of foregoing interbody arthrodesis after transthoracic discectomy. Transthoracic discectomy typically involves removal of the ipsilateral rib head, ipsilateral pedicle, and posterior vertebral bodies bordering the disk space. In the present series, most of the anterior part of the disk was left intact, preserving the anterior and posterior columns as described by Denis [6], thereby maintaining the normal intervertebral height and sagittal
Conclusions
The results of this study demonstrate the safety of foregoing bone grafting in patients undergoing thoracic discectomy. Clinical results are similar to the series in which grafting was performed. Radiographic follow-up did not demonstrate a deterioration in spinal alignment or axial spine pain. The need for fusion after transthoracic discectomy should be considered carefully and individualized. Future studies may better define the indications for interbody fusion after transthoracic discectomy.
Acknowledgment
The authors greatly thank Mr David Factor for the preparation of illustrations.
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