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Ann Thorac Surg 1995;59:1100-1106
© 1995 The Society of Thoracic Surgeons

Video-Assisted Thoracic Surgery for the Anterior Approach to the Thoracic Spine

Columbia HCA Medical Center and Institute for Spine and Biomedical Research, Plano, Texas; Townson Orthopaedic Associates, PA, Baltimore, Maryland; Kaiser Permanente Department of Orthopedics, Sacramento, California; and Orthopaedic and Sports Medicine Associates, PA, Emerson, New Jersey

	Abstract

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
Standard anterior approach to the thoracic spine is by a posterolateral thoracotomy. Because of the morbidity associated with this incision, video-assisted thoracic surgery (VATS) has been used as a less invasive approach for many intrathoracic disease processes. We have applied VATS for anterior access to the thoracic spine. From April 1991 to September 1994, 95 patients underwent thoracic spine procedures using thoracoscopy as the sole method of anterior approach. Procedures performed include discectomy for herniation (n = 57), multilevel discectomy for correction of spinal deformity (27), corpectomy (9), and drainage of intervertebral disc space abscess (2). All levels of the thoracic spine from the T2–T3 level to the T12–L1 interspace were approached. Forty-four procedures were performed through the left side of the chest and 41 through the right. The planned procedure was accomplished by VATS in all but 1 patient who required conversion to an open procedure because of scarring from a previous spine procedure. Mean operative time was 2 hours 24 minutes (range, 45 minutes to 5 hours 10 minutes). Average chest tube duration was 1.4 days, and mean length of stay was 4.82 days (range, 2 to 21 days). Complications included intercostal neuralgia (6), atelectasis (5), excessive epidural blood loss (2,500 mL; 2) and temporary paraparesis in a scoliosis patient related to operative positioning. We conclude that VATS offers a new, less morbid anterior approach to the thoracic spine. Although there is a significant learning period, most procedures requiring an anterior access can be performed safely by this technique. The VATS approach mandates an expanded role for the thoracic surgeon in operative spine disease.

	Introduction

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
See also page 1106.

The standard anterior approach to the thoracic spine is by a posterolateral thoracotomy or a thoracolumbar incision [1–3]. Although the exposure is excellent, the morbidity including postthoracotomy pain and associated respiratory problems is significant. This assumes greater significance when a concomitant or subsequent posterior procedure is necessary. Video-assisted thoracic surgery (VATS) has been documented to offer a less morbid approach to the management of many intrathoracic disease processes [4]. After gaining experience in performing many simple operative procedures by the endoscopic approach [5], we gradually have evolved to applying the thorascopic technique to more advanced procedures including those on the thoracic spine. We report our current experience using VATS in thoracic spinal surgery.

	Patients and Methods

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
Centers and Patient Selection
The procedures were performed in three medical centers: The Texas Back Institute, HCA Medical Center Plano, Plano, TX; The Scoliosis and Spine Center, St. Joseph's Hospital, Baltimore MD; and Kaiser Permanente, Sacramento, CA. All teams had collaborated closely together to develop the surgical principles and techniques in the animal model, and maintained close cooperation during the development of the surgical experience. This was accomplished by interchange of surgeons between each surgical center as well as periodic in vivo animal laboratory sessions with all surgeons involved.

Patients with thoracic spine diseases who are candidates for surgical intervention are informed fully of the availability of a video-assisted technique for performance of the surgical procedure, and informed consent is obtained. The option of having the surgical procedure performed by an open approach as well as the possibility of conversion of a thoracoscopic procedure to an open one is discussed fully with all candidates.

A plain roentgengram of the thoracic and lumbar spine is obtained before operation to ascertain the number of thoracic and lumbar vertebrae present as a baseline for subsequent intraoperative localization of the correct level of pathology. In all cases of suspected disc herniation, a computed tomographic myelogram or magnetic resonance imaging scan is obtained to confirm presence of pathology, ascertain the correct level, and correlate with clinical symptomatology.

Operative Technique
The patient is admitted to the hospital on the morning of operation, and after preoperative sedation, a double-lumen endotracheal tube is placed for administration of general anesthesia. All procedures are performed in the lateral decubitus position. Caution is used in positioning patients, especially those with spinal deformity.

Routine intraoperative monitoring for thoracic procedures is employed including an arterial pressure line, pulse oximeter, and end-tidal CO₂ measurement. Somatosensory evoked potentials are monitored routinely only for patients undergoing spinal deformity correction or corpectomy.

The initial trocar is placed, as in our usual VATS procedures, in approximately the seventh intercostal space in the posterior axillary line. A 10-mm trocar is used through which a 10-mm 30 degree angled rigid telescope is placed. Contrary to our other VATS procedures in which we employ a 0 degree end-viewing scope, we have found the 30 degree scope to be essential for direct vision to the intervertebral disc space without either impeding surgical instrumentation or obscuring the operative field.

In contradistinction to our standard VATS arrangement of trocars in a inverted triangle, we have found that placing the viewing port in the posterior axillary line directly over the spine and two or three access sites for working ports in the anterior axillary line allows better access to the spine. This ``reverse L'' arrangement can be moved cephalad or caudad depending on the level of the thoracic spine to be approached.

The portals are used for placement of surgical instrumentation as illustrated in Figure 1. By rotating the patient anteriorly and placing in a Trendelenburg position for the lower thoracic spine or reverse Trendelenburg for the upper thoracic spine, the lung usually will fall away from the operative field when completely collapsed, obviating the need for retraction instruments.

View larger version (32K): [in this window] [in a new window]   Fig 1. . Typical thoracoscope and instrument placement for thoracic spine procedures. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

View larger version (34K): [in this window] [in a new window]   Fig 2. . Position of the operative team for the procedure. Note the positions of both spine and thoracic surgeon on the anterior side of the patient. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

DISCECTOMY FOR HERNIATED NUCLEUS PULPOSUS.
At the appropriate level, the parietal pleura over the head of the rib is scored using monopolar cautery for approximately 6 cm. The borders of the rib are defined and the head of the rib clearly delineated (Fig 3). Using an air drill or osteotome, the rib is divided laterally (Fig 4), and with an elevator, the fascial attachments are divided. The rib portion then is removed through one of the trocar sites. This bone subsequently can be used as a rib strut or morselized into bone chips if fusion is necessary. The superior portion of the pedicle then is removed partially and the posterior longitudinal ligament and dural sac visualized (Fig 5). Bleeding from the epidural venous plexus can be problematic at this stage of the procedure. Control can be quite difficult and judicious use of bipolar cautery or gentle tamponade may suffice. More frequently, by application of constant, gentle suction to the operative field, adequate visualization may be obtained and the herniated disc decompressed expeditiously. If bleeding persists, however, temporary placement of a plug of microfibrillar collagen (Endo-Avitene; MedChem Products, Inc, Woburn, MA) will suffice. The herniated disc is swept away from the dura under direct vision (Fig 6). When it is judged that all pathologic material has been removed, a Penfield probe is placed and roentgenographic confirmation of decompression across the midline is obtained.

View larger version (132K): [in this window] [in a new window]   Fig 3. . Exposure for discectomy. Head of the rib is exposed by opening the parietal pleura. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

View larger version (134K): [in this window] [in a new window]   Fig 4. . Rib is divided and the head removed to expose the pedicle. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

View larger version (135K): [in this window] [in a new window]   Fig 5. . Visualization of the posterior longitudinal ligament and the epidural sac. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

View larger version (144K): [in this window] [in a new window]   Fig 6. . Using a curette, herniated disc material is swept away from the posterior longitudinal ligament and dural sac. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

View larger version (105K): [in this window] [in a new window]   Fig 7. . Discectomy performed for correction of spinal deformity. (Reproduced from Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery, St. Louis, MO: Quality Medical Publishing, Inc, 1995, by permission.)

At the completion of the spine procedure, the chest cavity is irrigated meticulously and all bony and cartilaginous debris removed. A 28F chest tube is placed through the low, posterior trocar site and the lung re-expanded. Care in an intensive care unit usually is not necessary. Pain relief is obtained with morphine or meperidine administration through a patient-controlled analgesia pump until the chest tube is removed, after which time oral analgesics suffice. The chest tube is removed when drainage is less than 150 mL per 24 hours, which is usually the first postoperative day. The patient is mobilized immediately and discharge usually occurs on the third postoperative day depending on the procedure performed.

	Results

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
From May 1991 through September 1994, 95 patients underwent thoracoscopic spinal procedures. The procedures performed at each institution were as follows: Texas, 55 patients; Baltimore, 20 patients; and Sacramento, 20 patients. There were 54 male and 41 female patients. The age depended on the procedure being performed. The patients undergoing anterior release for scoliosis or kyphosis had a mean age of 19.0 years (range, 2 to 44 years); the discectomy patients had a mean age of 42.1 years (range, 22 to 84 years). Patients undergoing corpectomy, usually for metastatic disease with incomplete neurologic deficits, had a mean age of 52.1 years (range, 28 to 84 years). The thoracoscopic procedures performed are listed in Table 1.

The mean operative time was 2 hours 24 minutes (range, 45 minutes to 5 hours 10 minutes). The planned procedure was able to be accomplished in all but 1 patient who required conversion to an open thoracotomy because of scarring from a previous posterior costotransversectomy.

Postoperative stay in an intensive care unit was used for care in 29 patients (31%). This is a reflection of our early experience and institutional bias. Currently, intensive care unit care seldom is necessary. Average chest tube duration was 1.44 days (range, 0 to 3 days). Mean postoperative length of stay was 4.82 days (range, 2 to 21 days).

Intraoperative blood loss was related to the type of procedure being performed, being less for anterior release procedures and higher for discectomy or corpectomy. Excessive blood loss occurred in 2 patients, but no patients required conversion to an open procedure because of bleeding. Two patients in the entire series required blood transfusion. One patient undergoing discectomy received one unit of autologous blood. Another patient who had a corpectomy for tumor required two units of blood. There was no operative mortality, but complications occurred in 15 patients (16%) and are listed in Table 2. Six patients suffered significant postoperative intercostal neuralgia; however, all incidents resolved within 6 weeks. Another 5 patients had postoperative atelectasis significant enough to prolong hospital stay for respiratory therapy.

There were no permanent iatrogenic spinal neurologic injuries. However, in 1 patient with scoliosis undergoing an anterior release procedure from T5 to T10 temporary paraparesis developed from an occult spinal stenosis at the T12–L1 level.

There were no infectious or postoperative wound complications.

Results were related to the type of procedure being performed. Forty-nine patients (86%) received significant or total relief of their preoperative symptoms. Twenty-three patients (40%) had complete relief of pain. Twenty-six patients (46%) had moderate to marked relief of symptoms requiring only occasional oral nonnarcotic analgesia. Eight patients (14%) had the same symptoms at follow-up (average, 9 months) as preoperatively. Of these, 4 had received relief immediately but suffered recurrent symptoms within 2 months of operation.

Release of spinal curvature sufficient for satisfactory correction of the deformity occurred in all patients. The average correction was a 70% improvement in degree of curvature with at least a 50% correction occuring in all patients.

Adequate neurologic decompression was obtained in all corpectomies, and both pyogenic intervertebral disc space abscesses were drained successfully.

	Comment

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
The anterior approach to the thoracic spine traditionally has been by thoracotomy, being first described in 1956 by Hodgson and Stock [6] for the treatment of Pott's disease. Cook in 1971 [7] and Richardson and associates in 1976 [8] described the role of the thoracic surgeon with the orthopedic or neurosurgical spine surgeon in providing anterior access to the vertebral column. This role was further expanded and defined by Smith and colleagues [9]. McElvein and associates [2] described the transthoracic and thoracolumbar approach in 45 patients undergoing a wide variety of spine procedures for diseases including deformity, trauma, and neoplasm. Anderson and associates [1] reviewed the Emory experience of 46 transthoracic or thoracolumbar approaches in 36 patients, which was presented at this meeting 2 years ago. The role of the thoracic surgeon in enhancing preoperative assessment, operative exposure, and closure as well as postoperative care was emphasized. It is interesting that the discussion of that presentation conjectured upon the use of thoracoscopy for ``exposing these spinal areas thoracoscopically.'' Naunheim and associates [3] described their results in 126 patients; the operative mortality was 3.2% and the considerable perioperative risk was noted.

We began our experience in VATS in 1990, and it became apparent to us that this approach provided excellent exposure to the anterior thoracic spine. Our initial VATS experience was limited to simple procedures on the lung and pleura [5]. However, as we gained more experience in thoracoscopic techniques, more complex surgical procedures became possible. Our initial thoracoscopic spine procedures (disc space abscess) were hindered by the false presumption that CO₂ insufflation was necessary, and our instrumentation was therefore limited and not appropriate for orthopedic procedures. When it became apparent that an open ``gasless'' approach was possible, standard orthopedic instrumentation was able to be employed [10]. Although this improved the technical feasibility, these instruments were not optimal for the thoracoscopic approach mainly because of inadequate length. Subsequent instrument modifications including elongation to approximately 30 cm and angulation of instrument tips has facilitated successful execution of the endoscopic procedures greatly.

The results in our series compare favorably with those of other series of spine procedures approached anteriorly in the literature [11–13]. Complications appear to be less than in patients approached via thoracotomy and there appear to be shorter operative times, hospital stay, and blood loss compared with open series.

Significant complications in our experience include intercostal neuralgia. This is a bothersome postoperative symptom, especially in patients in whom radicular pain from disc herniation was the indication for the procedure. There appear to be a number of causes of and solutions to this problem. Pressure on the intercostal nerve during the procedure is the most apparent cause. This can be lessened by the use of smaller, rigid trocars (most endoscopic orthopedic instrumentation is 10 mm in diameter) or by the use of flexible trocars, which compress and conform to the intercostal space, presumably causing less pressure on the intercostal nerve. Small chest tubes (24F to 28F) should be used for postoperative drainage. Instrument levering and torque can cause significant intercostal nerve compression. Both proper placement of trocars at the target thoracic spine level and use of a 30 degree angled scope can minimize pressure on the intercostal nerve. Injury to the intercostal nerve also can occur from monopolar electrocautery at the time of resection of the head of the rib. Avoidance of monopolar cautery along the inferior border of the rib therefore is preferable.

In 1 patient with scoliosis transient paraparesis developed postoperatively at a level below the operative site. In retrospect, we believe this may have been due to operative positioning to widen the intercostal spaces and drop the hip so that maximum excursion range was present. We now avoid excessive flexing of the operative table at the hip to minimize any possible spinal cord stretching.

At present, we have converted most spine procedures to the thoracoscopic approach [14]. Since completion of this series of patients, we have successfully implanted a BAK cage (Spinetech, Inc, Minneapolis, MN) specifically designed for endoscopic placement in 5 patients. We anticipate that this may facilitate spinal fusion by minimally invasive techniques.

Indications for operative intervention by the thoracoscopic approach remain the same as for the open thoracotomy approach. Procedures not appropriate for the thoracoscopic approach are some that require anterior instrumentation for stabilization. Fractures or tumors with three-column spinal instability or thoracolumbar scoliosis, which requires anterior placement of instrumentation for stabilization, are not appropriate for this method of access at the present time. Limited stabilization with rib struts as in our corpectomy patients now can be performed thoracoscopically. With the development of stabilization devices suitable for endoscopic placement, these conditions requiring greater stabilization eventually may be approached endoscopically. Most other spine procedures traditionally approached anteriorly can be performed thoracoscopically. In addition, because of the excellent exposure provided by this new, less invasive anterior approach, the posterior approaches may become less common. Relative contraindications include pleural symphysis from previous surgical procedures or preexisting pleural disease.

We conclude that VATS offers a new, minimally invasive approach for the treatment of most thoracic spine disorders that require surgical intervention. Surgical techniques and instrumentation have improved so that the same surgical procedures can be performed by the thoracoscopic approach as previously accomplished by open techniques. There is a significant learning curve to the procedures, and a spine surgeon who has received training in endoscopic techniques as well as a thoracic surgeon well versed in thoracoscopy are both necessary. This spine surgeon–thoracic surgeon team first should gain experience in the animal laboratory or from a specific endoscopic spine course that includes a laboratory experience. Appropriate applications of VATS are evolving slowly for many diseases, and we are encouraged by its role in approaching thoracic spine disease.

	Footnotes

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 
Presented at the Forty-first Annual Meeting of the Southern Thoracic Surgical Association, Marco Island, FL, Nov 10–12, 1994.

Address reprint requests to Dr Mack, 7777 Forest Lane, Suite 323-A, Dallas, TX 75230.

	References

Top Footnotes Abstract Introduction Patients and Methods Results Comment References

 

1. Anderson TM, Mansour KA, Miller JI. Thoracic approaches to anterior spinal operations: anterior thoracic approaches. Ann Thorac Surg 1993;44:1447–52.
2. McElvein RB, Nasca RJ, Dunham WK, et al. Transthoracic exposure for anterior spinal surgery. Ann Thorac Surg 1988;45:278–83.[Abstract]
3. Naunheim KS, Barnett MG, Crandall DG, et al. Anterior exposure of the thoracic spine. Ann Thorac Surg 1994;46:1436–9.
4. Landreneau RJ, Hazelrigg SR, Mack MJ, et al. Postoperative pain-related morbidity: video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56:1284–9.
5. Mack MJ, Aronoff RJ, Acuff TE, et al. The present role of thoracoscopy in the diagnosis and treatment of diseases of the chest. Ann Thorac Surg 1992;54:403–9.[Abstract]
6. Hodgson AR, Stock FE. Anterior spinal fusion: a preliminary communication of radical treatment of Pott's disease and Pott's paraplegia. Br J Surg 1956;44:266–75.
7. Cook WA. Transthoracic vertebral surgery. Ann Thorac Surg 1971;12:54–68.[Medline]
8. Richardson JD, Campbell DL, Grover FL, et al. Transthoracic approach for Pott's disease. Ann Thorac Surg 1976;21:552–6.[Abstract]
9. Smith TK, Stallone RJ, Yee JM. The thoracic surgeon and anterior spinal surgery. J Thorac Cardiovasc Surg 1979;77:925–8.[Medline]
10. Mack MJ, Regan JJ, Bobechko WP, et al. Application of thoracoscopy for diseases of the spine. Ann Thorac Surg 1993;45:736–8.
11. Alband OW, Corkill G. Thoracic disk herniation. Treatment and prognosis. Spine 1979;4:41–6.[Medline]
12. Bohlman HH, Zdeblick TA. Anterior excision of herniated thoracic discs. J Bone Joint Surg 1988;70A:1038–47.[Abstract/Free Full Text]
13. Otani K, Yoshida M, Fujii E, Makai S, Shibasaki K. Thoracic disk herniation. Surgical treatment in 23 patients. Spine 1988;13:1262–7.[Medline]
14. Regan JJ, McAfee PC, Mack MJ, eds. Atlas of endoscopic spine surgery. St. Louis: Quality Medical Publishing, 1995.

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This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mack, M. J. Articles by Acuff, T. E. Search for Related Content PubMed PubMed Citation Articles by Mack, M. J. Articles by Acuff, T. E.