Arthroscopic discectomy and interbody fusion of the thoracic spine: A report of ipsilateral 2-portal approach

Abstract

Background: The standard approach to the thoracic disc is through thoracotomy. The video-assisted thoracoscopic approach has been used as an alternative to the open approach for nearly 20 years, and more recently, extracavitary, posterolateral approaches have been introduced. Both the transthoracic procedures involve deflating the lung for access to the spine, and postoperative thoracic drainage is necessary; postoperative morbidity can be significant. The retropleural procedures are in their infancy, but the published results are promising. The purpose of this study is to introduce the posterolateral arthroscopic thoracic decompression and fusion procedure, which is extrapleural, less disruptive to normal anatomy, and cost-effective.

Methods: Fifteen consecutive patients who underwent arthroscopic decompression and interbody fusion of the thoracic spine were prospectively studied according to the hospital's institutional review board protocol. The Short Form 36 and visual analog scale questionnaires were completed preoperatively and postoperatively. Paired t tests were used for statistical analysis. The patient was placed in the prone position on a radiolucent table, and instrumentation was performed under fluoroscopic control. Two portals were developed ipsilaterally (one for the arthroscope and the other for instruments) on the side of disc herniation, and a single portal was used on the contralateral side. Various instruments were used for disc excision and exploration of the spinal canal. Fusion was accomplished with bilateral corticocancellous dowels obtained from the iliac crests. Infiltration of the access channel and facet injections of the contiguous joints were performed with bupivacaine, for immediate postoperative pain control.

Results: Fifteen patients with a mean age of 54 years were followed up for 28 months postoperatively. The overall back pain score decreased from 7.2 (SD, 1.5) to 3 (SD, 2) after the procedure (P < .005). Eleven patients were satisfied with their current lifestyle postoperatively as opposed to one preoperatively. Two patients had reoccurrences. Hospital stay averaged 18.5 hours. The operating room cost and the cost of hospital stay was 51.9% of the cost of anterior open discectomy.

Conclusions: The extrapleural, biportal, ipsilateral arthroscopic approach for the decompression and interbody fusion of the thoracic spine is feasible, cost-effective, less traumatic, and associated with minimal complications. The best results were obtained in patients with single-level thoracic disc herniation. The technique is applicable for most thoracic disc herniations.

Keywords: Bone dowels; Discectomy; Endoscopic; Fusion; Posterolateral; Retropleural.

Fig. 1

Operating room set-up, note the laterally transparent drape. This allows the surgical team see foot pedals on the floor, and the fluoroscope as it is placed in the lateral position.

Fig. 2

Patient in prone position on the operating table. Note skin markings indicating spinal levels and iliac crests, prior to skin preparation and sterile draping.

Fig. 3

Intra-operative, anteroposterior fluoroscopic view of guide wires triangulating in the foraminal canal of the target motion-segment.

Fig. 4

Illustration of unilateral, bi-portal approach to a thoracic foramen. Note in this illustration the arthroscope is the rostral cannula.

Fig. 5

Unilateral bi-portal arthroscopic approach to the thoracic spine. Note the arthroscope and the instrument in the surgeon's left, and the right hand, respectively.

Fig. 6

Arthroscopic view of the grasping forceps in the disc space.

Fig. 7

After excision of a large calcified herniated disc material from within the disc space, a Penfield #4 probe is inserted between the posterior annulus and the dura, to decompress the epidural space.

Fig. 8

Arthroscopic view of the dura, after excision of a large herniated and calcified intervertebral disc.

Fig. 9

Anteroposterior fluoroscopic view of bone dowel being place in the intervertebral disc space, through one of the cannulas.

Fig. 10

Thoracic levels of degeneration/herniation which were operated on.

Fig. 11

Overall pain severity score preoperatively and postoperatively. The difference was statistically significant (P ≤ .005).

Fig. 12

Preoperative and postoperative level of satisfaction with life as a result of spine-related symptoms. The difference was statistically significant (P ≤ .005). ES, extremely satisfied; MX, mixed reaction; SD, somewhat dissatisfied; SS, somewhat satisfied; VD, very dissatisfied; VS, very satisfied.

Fig. 13

Preoperative and postoperative salaried work status, showing the number of hours patients were able to work per week as a result of spine-related symptoms. (NW-Other, not working for non–spine-related reason; NW-Retired, not working because of retirement; NW-SP, not working because of spine-related symptoms; W 40, working 40 hours per week.)

Fig. 14

4 months post-operative CT Scan of interbody fusion of the thoracic spine.