Indications

Scoliosis

Thoracic scoliosis has various etiologies (idiopathic, neuromuscular, syndrome related) that are frequently not diagnosed and treated until the curve is relatively large and stiff. Anterior surgery has been most frequently used as a means to achieve a complete discectomy and release of the anterior spine; this results in greater curve flexibility and prevents the “crankshaft” phenomenon in young patients. Although no strict guidelines on the magnitude and flexibility of the spinal curvature that requires release have been established, generally curves with a Cobb angle greater than 70 to 75 degrees and a bend correction less than 50% are considered appropriate for release. When sufficient segmental mobility of the released vertebra has been achieved, posterior instrumentation is placed to correct the deformity (Fig. 25–1).

FIGURE 25–1 A and B, Preoperative posteroanterior (A) and lateral (B) radiographs of large stiff curve. C and D, Postoperative posteroanterior (C) and lateral (D) radiographs. Thoracoscopic anterior spinal release and discectomy and combined posterior spinal instrumentation and fusion provide acceptable correction.

Lenke³ reported on a combined anterior VATS release and fusion followed by posterior instrumentation in the treatment of adolescent idiopathic scoliosis that had an average preoperative curve of 82 degrees (range 41 to 125 degrees) with postoperative correction of 70% to 28 degrees (range 5 to 60 degrees). Similarly, Newton and colleagues⁴ reported a series of 112 pediatric spinal deformity cases with an average preoperative curve of 80 degrees that received an anterior release combined with posterior instrumentation and found a 67% correction in idiopathic scoliosis and a 52% correction in neuromuscular scoliosis. More recent studies have called into question the utility of the anterior release, however, in the age of modern segmental pedicle screw instrumentation.^5,6 Suk and colleagues⁶ found an average correction of 66% when posterior pedicle screws alone were used in preoperative thoracic curves of 80 degrees with a flexibility of 45%. Although modern pedicle screw constructs offer a similar correction, an anterior release may still be indicated to optimize coronal and axial plane correction, improve sagittal alignment by increasing thoracic kyphosis, and prevent crankshaft growth.

Children and young adolescents (Risser 0, open triradiate cartilage) with progressive scoliosis are known to be at risk for crankshaft deformity when treated with a posterior fusion alone.⁷ These results were reported for children using hook and wire fixation, however, and not modern pedicle screw instrumentation. Although there has been concern regarding adequate pedicle size in children to accommodate pedicle screws, Catan and colleagues⁸ performed a magnetic resonance imaging (MRI) analysis of thoracic pedicle morphology in preadolescent patients with idiopathic scoliosis and found that the anatomic measurements were compatible with pedicle screw instrumentation. Sarlak and colleagues⁹ reported more recently a series of seven children (average age 7.4 years) with scoliosis with an average preoperative thoracic curve of 56 degrees who were treated with posterior segmental pedicle screw instrumentation and 5 years of follow-up. These authors found a 57% correction rate with no evidence of crankshaft phenomenon in four patients but found a slight increase in Cobb angle and a significant increase in angle of trunk rotation (ATR) suggesting crankshaft phenomenon in two patients.⁹ Given the lack of clear evidence on the appropriate treatment of these cases, an anterior fusion may be a viable option to limit anterior growth and prevent this late increasing deformity.¹⁰ Thoracoscopic disc excision and fusion provides a minimally invasive option and minimizes the risk of pulmonary complications in these young patients with progressive deformity.^11–13

Patients with spinal deformity associated with Marfan syndrome, neurofibromatosis 1, and prior spinal irradiation may have an increased risk of pseudarthrosis after an isolated posterior scoliosis correction. In cases such as these, an anterior fusion procedure may improve the odds of successful arthrodesis, especially when autogenous bone graft is used.⁴

Contraindications

As suggested earlier, the small size of the patient is a relative contraindication to thoracoscopy. Lung deflation is more difficult in these cases because standard size double-lumen and bronchial blocking endotracheal tubes are too large. Another contraindication is the presence of a markedly reduced working distance between the chest wall and the spine. In severe cases of scoliosis, the reduced distance limits the field of vision (the endoscope is too close to the spine to obtain any perspective) and the maneuverability of the working instruments. A minimum distance of 2 to 3 cm of working space between the rib cage and the spinal column is required to provide adequate visualization. If the distance is less than 2 cm, thoracoscopy is not advised. Body weight of less than 30 kg is a relative contraindication because the relative benefits of thoracoscopy seem to be reduced in small patients.²⁶

Visualization of the surgical field is mandatory in all surgical approaches, and it may be compromised in thoracoscopic surgery by incomplete deflation of the lung or pleural adhesions that prevent collapse away from the chest wall and spine. Pleural adhesions (Fig. 25–2) can be anticipated in patients with a history of prior ipsilateral thoracic surgery or significant pulmonary infection, both of which should discourage the surgeon from using the thoracoscopic approach.

FIGURE 25–2 Endoscopic view of pleural adhesions indicated by arrows A and B.

Surgical Technique

Much of the equipment required for spinal thoracoscopy is common to all endoscopic surgery. An endoscope (10-mm diameter, 0- and 45-degree angle viewing), video camera, light source, and monitor have become standard in nearly all modern operating rooms. Access through the chest wall between the ribs is maintained with plastic tubular “ports.” These ports provide a path to place the endoscope and working instruments into the chest cavity.

Patient positioning has traditionally been in the lateral decubitus position (Fig. 25–3). Some studies have suggested that in select cases prone positioning may be possible, avoiding the need to reposition the patient for the posterior procedure or even allowing simultaneous anterior release and posterior instrumentation.^27–29 Although the ability to convert to an open approach may be restricted, it has been shown that the prone position does not adversely affect postoperative pulmonary function.³⁰ This approach necessitates a more posterior portal placement, however, and may limit the anterior extent of spinal exposure and disc excision.

FIGURE 25–3 Diagrammatic setup in operating room shows position of surgeon, assistants, scrub nurse, and monitor for endoscopic surgery.

The role of the anesthesiologist is crucial in the success and safety of thoracoscopic surgery.³¹ Spinal cord monitoring is advised using somatosensory and transcranial motor evoked potentials. Complete ipsilateral lung deflation is essential to prevent lung parenchymal injury from passing instruments and to allow visualization of the spine. Double-lumen endotracheal tubes are preferred in patients large enough (>45 kg) to accept these devices. In children (<45 kg), selective intubation of a single lung is often required as an alternative. A small balloon advanced into the main stem bronchus blocks ventilation to the lung on the operative side. In nearly all patients with normal preoperative pulmonary function, single-lung ventilation can be tolerated. The surgeon and anesthesiologist should be aware of the increased risk of developing postoperative mucous plugs as a result of single-lung ventilation.

After lung deflation, portals are established through the chest wall (Fig. 25–4). The orientation of these portals may vary depending on the pathology, although in most cases of deformity release and fusion they are best placed in a linear relationship along the anterior axillary line. Owing to the site of diaphragm insertion, the inferior portals require a slightly more posterior placement to maintain an intrathoracic position. Initial exposure of the spine often requires gentle retraction of the lung, at least until it becomes completely atelectatic (Fig. 25–5). The vasculature including the azygos vein and subclavian artery is identified before the introduction of surgical instruments to prevent inadvertent injury (Fig. 25–6). The vertebral levels are confirmed by identifying the first rib partially hidden beneath the subclavian artery and counting down distally (Fig. 25–7). Division of the pleura overlying the spine may be performed either longitudinally, over the length of the spine to be fused, or transversely, at each disc space.

FIGURE 25–4 Proper placement of portals is necessary for multilevel discectomies with the patient in lateral position.

FIGURE 25–5 Intraoperative endoscopic view of fan retractor (A) placed on lung (B) to aid in complete deflation.

FIGURE 25–6 Endoscopic view of thoracic cavity shows spine (asterisk), segmental vessels, azygos vein (arrow), and atelectatic lung.

FIGURE 25–7 Peanut dissector is used to palpate first rib (A). Second rib (B) is most obvious.

Treatment of the segmental vessels (Fig. 25–8) may be similarly individualized with either division or preservation, depending on the needs of the case or preference of the surgeon. In most cases, the authors prefer a longitudinal pleural exposure with division of the segmental vessels using Harmonic laparoscopic coagulating sheers (Ethicon Endo-Surgery, Cincinnati, Ohio). Division of the segmental vessels allows greater anterior spinal exposure for more complete annular release. Blunt dissection of the pleura to the contralateral side of the spine is performed exposing approximately 270 degrees of the disc perimeter. After division of the pleura, any remaining areolar tissue is divided, and packing sponges are used to create a space between the anterior spine and the pleura.

FIGURE 25–8 After division of pleura (A), Harmonic laparoscopic coagulating sheers are applied to segmental vessel (B).

Possible levels that can be accessed thoracoscopically are T2-L1. Exposure of the T12-L1 disc and L1 vertebral body requires division of a small segment of the diaphragm insertion, which can be accomplished by extending the pleural incision distally into the diaphragm. The proximal thoracic spine in the right chest is often covered by the confluence of the segmental veins, which may appear daunting at the T3 and T4 levels. With slow cautious use of the ultrasonic devices, these vessels can be sealed and divided safely, however, exposing the upper thoracic spine. Disc excision techniques are similar to techniques used in open surgery. An annulotomy is performed with the electrocautery or Harmonic scalpel. A rongeur is an excellent tool for most of the disc excision. Specially designed endoscopic rongeurs are available in extended lengths with various angles (straight, up, right, left) to reach the depths of each disc space (Fig. 25–9).

FIGURE 25–9 A, Discectomy can be done with rongeur or curet or both with complete removal of anulus fibrosus, nucleus pulposus, and both endplates of cartilage. B, Appearance after multilevel discectomies completed. Empty disc space can be temporarily packed with Surgicel for hemostasis control before application of bone graft.

Awareness of the discectomy path is vital to avoid damage to the neural elements and to prevent excess bone excision, which causes increased bleeding and suboptimal visualization. An angled curet may also be used to remove residual endplate cartilage and expose the cancellous bony surface required for fusion. Bleeding from the bone can be limited by using the avascular plane of dissection between the cartilage endplate and the vertebral body in immature patients. The key to a comprehensive discectomy is optimal visualization deep into the disc space; this not only allows complete removal of all disc tissue, but also prevents injury to the posterior longitudinal ligament and neural elements.

When the discectomy is complete, either allogeneic cancellous or autogenous (rib or iliac crest) bone graft is placed into the disc space with an endoscopic tubular plunger (Fig. 25–10). The method and type of bone grafting also seems to be important to the success of arthrodesis. This may be crucial only in selected cases; however, all patients are at some risk for pseudarthrosis after posterior instrumentation and fusion procedures. In a study of 112 patients treated with an anterior release followed by posterior instrumentation, Newton and colleagues⁴ compared the grade of arthrodesis between patients who received autogenous versus allogeneic bone graft. These authors found the disc space was fused in 88% of the autograft group compared with 72% of the allograft group at 2-year follow-up.⁴ When autograft is not available, either allograft bone or demineralized bone matrix may be used because they have been shown to result in similar fusion rates.^4,32 Although autogenous bone graft is optimal for patients at greatest risk for pseudarthrosis, the risk-to-benefit ratio must be analyzed on a case-by-case basis.

FIGURE 25–10 Morcellized bone graft (arrow) is introduced into disc space using tubular plunger (asterisk).

Outcomes

The thoracoscopic approach has several advantages compared with an open thoracotomy approach. These advantages, including pulmonary function, reduced recovery period, less pain, and improved cosmesis, are realized, however, only if the efficacy of the spinal procedure equals that of open surgery. Experimental animal and clinical studies suggest comparable efficacy in experienced hands. Several studies have been conducted to evaluate the learning curve necessary to be experienced in this technique.^12,33,34 Newton and colleagues¹² found that there was a slight decrease in operative time throughout the course of the first 65 patients treated at their institution and concluded that thoracoscopy had a steep but not prohibitive learning curve. In a more recent study by Son-Hing and colleagues,³³ the learning curve was found to be short with appropriate training and resulted in an excision of a greater amount of disc tissue and a decrease in operative time, while providing similar curve correction to an open thoracotomy.

Several experimental studies have been done to analyze the extent of disc excision possible with thoracoscopic techniques. Biomechanical evaluations of the instability resulting from discectomy were equivalent between open and endoscopic approaches in various animal models.^34–37 The extent of endplate bony exposure has also been shown to be similar with the two approaches experimentally.^34,38 In a histomorphometric study of 32 pigs (160 discs), Zhang and colleagues³⁴ found that there was not a learning curve associated with the amount of disc material excised (>50% in 94% of the discs in this study), but a learning curve was present for the thoroughness of the endplate excision in thoracoscopic discectomy. Because the purpose of the endplate excision is to remove the growth potential and expose a cancellous bony surface for fusion, added care must be taken during the endplate removal step of this procedure.

The clinical results of thoracoscopic anterior release and fusion in patients with spinal deformity have been generally favorable although poorly controlled.³⁹ Although there was an increase in the use of this method during the 1990s, it has since declined in popularity with the widespread adoption of posterior segmental pedicle screw instrumentation. Despite more recent studies that have called the necessity of this technique into question for large, stiff curves, there may be a subset of patients who benefit from this procedure.^5,6,40 Studies by Luhmann and colleagues⁵ and by Suk and colleagues⁶ looked at curves with an average of 80 degrees main thoracic Cobb angle and an average flexibility of 45%. Both groups of investigators concluded that a similar coronal correction can be achieved with posterior segmental pedicle screw fixation as with a combined anterior and posterior procedure. These studies did not examine deformity on the extreme end of curves greater than 100 degrees with less than 25% flexibility, however. In a more recent study of 21 patients with an average preoperative Cobb angle greater than 110.5 degrees and flexibility of 13%, Yamin and colleagues⁴⁰ found a staged procedure to provide a safe and effective treatment with a mean correction rate of 65.2%. These authors recommended that patients with a Cobb angle greater than 80 degrees and flexibility less than 20% should be treated with a staged anterior release and posterior pedicle screw instrumentation with the addition of halo-pelvic traction to correct the deformity.⁴⁰

Evaluation of VATS perioperative and postoperative data reveals an increase in operative time compared with open thoracotomy but a decrease in blood loss, chest tube drainage, and pulmonary morbidity and an increase in patient satisfaction. The time to perform thoracoscopic surgery has ranged from 90 minutes to 4 hours with a decrease in operative time as experience is gained. The total operative time per disc level excised averages 20 to 40 minutes. Studies on the learning curve for VATS have been performed by Newton and colleagues¹² as well as by Son-Hing and colleagues.³³ VATS operative time decreased 26% to 30% and operative time per disc decreased 15% to 24% between the first seven and last seven patients in both series.^12,33 As surgeons gain experience with improved thoracoscopic techniques, instrumentation, and training, the operative time has been shown to be less for VATS compared with an open approach.³³

The reported blood loss and chest tube drainage have been comparable to open procedures with blood loss generally averaging less than 300 mL.^12,33,41,42 In cases of excessive blood loss, conversion to open thoracotomy may be required. The incidence of major complications for either VATS or open thoracotomy is less than 1%.^12,33,43 The most common complications associated with VATS are pulmonary, such as atelectasis, pleural effusions, pneumothorax, and excessive chest tube drainage.^12,33,42,43 Faro and colleagues⁴⁴ compared pulmonary function after an open versus a thoracoscopic anterior procedure and found that pulmonary function recovered more quickly with VATS, and this difference was maintained after 2 years of follow-up. As with all anterior spinal surgery, these risks exist and must be minimized. Although the instrumentation, techniques, and support for VATS continue to improve, this approach is technically demanding, and proper training is essential to the success of this procedure.

Indications

Anterior instrumentation and fusion has been used in various spinal conditions and studied extensively in adolescent patients with idiopathic scoliosis. Although the curve patterns amenable to this approach continue to be elucidated, in general, structural adolescent or adult (with normal bone density) thoracic curves may be considered for selective thoracic anterior instrumentation (Fig. 25–11).⁵⁰ A review of the pediatric spine literature reveals that anterior instrumentation and fusion has been primarily evaluated in moderate thoracic, thoracolumbar, and lumbar curves between 40 and 70 degrees with flexibility greater than 50%.^51,52 Anterior instrumentation and fusion is kyphogenic and may be a valuable tool in patients with significant hypokyphosis. Eight or fewer vertebrae may be included in the arthrodesis, and the fusion may extend from T4 to L1.⁵²

FIGURE 25–11 A, Preoperative posteroanterior and lateral radiographs of a patient with adolescent idiopathic scoliosis. B, Postoperative posteroanterior and lateral radiographs after thoracoscopic instrumentation from T5 to T12 with correction of deformity. C, Clinical appearance of the patient before and after thoracoscopic anterior instrumentation and fusion with excellent trunk balance and shoulder symmetry.

The radiographic parameters are not the sole indications; the decision to perform an anterior procedure must be considered in the context of the overall patient evaluation. The patient’s level of maturity and pulmonary status are also important factors to consider. Anterior fusion eliminates growth potential and may be useful in preventing crankshaft phenomenon; however, eliminating this potential in very young children may result in posterior column overgrowth (kyphosis). Specific age parameters have yet to be determined, and the decision must be made based on the needs of the individual patient and the surgeon’s experience.

Contraindications

Contraindications for thoracoscopic instrumentation are similar to the contraindications for anterior release and fusion. The procedure is contraindicated if the patient has severe or acute respiratory insufficiency. Previous severe respiratory infections and ipsilateral thoracic surgery are also relative contraindications because pleural adhesions complicate thoracoscopic visualization. In addition to general thoracoscopic contraindications, large stiff curves and hyperkyphosis measuring 40 degrees or greater (from T5 to T12) are relative contraindications. Patients with osteopenia or poor bone stock are also not good candidates for this technique. Additionally, in patients in whom a single rod construct is being considered, a seizure disorder and a suspicion that the patient would be noncompliant with postoperative orders are also contraindications because of concerns of implant loosening. Given that thoracoscopic visualization extends from T4 to L1, thoracoscopic instrumentation should not be attempted for double major curves or curves that extend beyond these end points.^52–54

Surgical Technique

Before surgery, full-length standing posteroanterior and lateral radiographs, side-bending radiographs, and pulmonary function tests are obtained. The same surgical technique principles apply as with a thoracoscopic release and fusion. Portal placement is the same as with a release procedure. Care is taken with the posterior portal placement along the posterior axillary line because screw placement in the posterior aspect of the vertebral bodies is accessed through these channels. After the portals are placed, a thorough discectomy and endplate preparation are performed as described previously for the anterior release and fusion surgical technique. Spinal instrumentation and curve correction is performed under the guidance of fluoroscopy and endoscopy.

Either a single-rod or dual-rod system may be used depending on the size of the vertebrae, the concerns for rod breakage, and the experience of the surgeon. Single-rod systems offer a greater ease of implantation; however, biomechanical studies have suggested that dual-rod constructs are more stable than single-rod constructs.^55,56 Also, in their series of 60 patients with 2 to 5 years of follow-up, Hurford and colleagues⁵⁷ reported that dual-rod constructs provided a similar curve correction rate to single-rod constructs but with a significantly improved SRS questionnaire outcome and no reported cases of pseudarthrosis. The length of the cephalad-most screw is templated on the preoperative posteroanterior radiograph (usually 27.5 or 30 mm), and this screw is placed first. The screws are optimally positioned 1 to 2 mm anterior to the rib head in the middle of the vertebral body with approximately 10 degrees of subtle anterior angulation.

The path of each screw is approximately parallel to the endplates (Fig. 25–12). Penetration of the far cortex greatly enhances the fixation and is mandatory at the proximal levels to reduce the risk of screw pullout. Care must be taken to avoid placing successive screws increasingly anterior in the vertebral body because this may negatively affect fixation and restoration of kyphosis and potentially place the aorta at increased risk of iatrogenic injury.⁵⁸ Although there have been concerns regarding vertebral body screws placed thoracoscopically, Qiu and colleagues⁵⁹ showed that there is no statistically significant difference in the accuracy of vertebral body screw placement in thoracoscopic versus mini-open thoracotomy approaches. When the proper screw length has been selected, a pilot hole is created with an awl and the tapped advanced under fluoroscopic guidance. A bicortical screw (5.5 to 7.5 mm in diameter) is placed into the vertebra. Screw position is confirmed again fluoroscopically, and the remaining screws are placed in a similar fashion.

FIGURE 25–12 Screws are placed along path parallel to endplates.

After all the screws are placed (Fig. 25–13), the length of the rod is determined with a calibrated rod-measuring device. A rod of appropriate length is cut and contoured to the desired level of postoperative scoliosis and kyphosis. The rod is sequentially loaded into the screws and secured with locking nuts (Fig. 25–14). Fully seating the rod into the screws may be accomplished with either a rod pusher or the use of a reduction device. Several styles of compressors have been developed to compress between levels. This compression is an important component to the anterior correction of scoliosis but must be performed in a cautious manner, particularly at the upper levels where screw fixation may be tenuous.

FIGURE 25–13 Care must be taken in screw placement to ensure that screws are aligned to accept rod.

FIGURE 25–14 Endoscopic view of locked single rod anterior screw and rod construct.

Bone grafting is crucial to the success of this procedure. As mentioned previously in the section on thoracoscopic release, autogenous graft provides the optimal base for a solid fusion and is recommended.^4,32 At the lower levels of the thoracic spine, distal to T11, structural anterior support may be required to aid in maintaining proper sagittal alignment.

Outcomes

In 1998, Picetti and colleagues⁶⁰ were the first to report a clinical case of multilevel anterior scoliosis correction performed thoracoscopically. Early studies reported high rates of pseudarthrosis, implant failure, and loss of fixation.^54,61,62 Since that time, the initial learning curve has been overcome,^12,63 and comparable results have been reported between thoracoscopic anterior procedures and open anterior and posterior techniques.* Early and midterm results of thoracoscopic anterior instrumentation have been favorable. In a series of 45 patients with adolescent idiopathic scoliosis, Norton and colleagues² found an overall curve correction 87.3% (51.6 degrees preoperatively to 6.6 degrees postoperatively), an average hospital stay of 2.9 days, and a return to school after 2 to 4 weeks. Newton and colleagues⁴⁶ reported that radiographic findings, pulmonary function, and clinical measures remained stable between 2 and 5 years’ follow-up in their series of 23 patients treated with VATS instrumentation. In the Norton series,² three patients had transient pulmonary complications, and in the Newton series,⁴⁶ three patients had an implant failure that necessitated a surgical revision in one patient. Both series found no significant loss of correction after an average 4.6-year (Norton series) and 5.3-year (Newton series) follow-up.

Although operative time is longer in VATS cases compared with an open anterior or posterior procedure, operative time does decrease with experience. Lonner and colleagues⁶³ reported a significant reduction in operative time from 6 hours in their first 28 cases to 4 hours 30 minutes in the last 15 cases. Studies by Lonner and colleagues¹³ and Wong and colleagues⁶⁵ compared VATS with standard posterior procedures and found a decrease in intraoperative blood loss and a reduced hospital stay in the Lonner study and a reduced intensive care unit stay in the Wong study. When pulmonary function is evaluated, VATS has been shown to result in better recovery of pulmonary function compared with open techniques and similar return to function as in standard posterior techniques.^13,44 Similarly, in regard to shoulder girdle function, Ritzman and colleagues⁶⁶ found that VATS was comparable to posterior instrumentation, which were both better than open anterior surgery. Further comparison by Lonner and colleagues¹³ of the impact of VATS versus posterior spinal instrumentation and fusion on the patients’ quality of life using the SRS-22 instrument revealed that patients who underwent VATS scored higher in the self-image, mental health, and total domains despite similar curve corrections.

In all of the aforementioned studies, VATS was compared with a mix of posterior spinal fusion instrumentation anchors (wires, hooks, screws). Although many of these past studies focused on the outcomes of thoracoscopic instrumentation compared with open anterior or posterior hybrid instrumentation, more recently VATS has been directly compared with posterior segmental pedicle screw constructs. Lonner and colleagues⁴⁵ performed a matched-pair analysis of 34 patients with adolescent idiopathic scoliosis with single thoracic curves of approximately 50 degrees. The patients had equivalent radiographic results, patient-based clinical outcomes, and complication rates with the exception that the posterior thoracic pedicle screw group had a slightly better major curve correction (63.8% vs. 57.3%). These authors concluded that VATS offers the advantages of reduced blood loss (371 mL vs. 1018 mL), fewer total levels fused (5.9 vs. 8.9), and preservation of nearly one caudal fusion level. The disadvantages included increased operative time (325 minutes vs. 246 minutes) and slightly less improved pulmonary function.

The evidence regarding which scoliosis patients would be the best candidates for VATS is unclear. The authors advise that the patient’s age, curve properties, and risk factors must be carefully considered in context of surgeon experience when electing to use this approach. Although posterior pedicle screw instrumentation remains the “gold standard,” VATS may still play a valuable role in optimally selected patients.

Tumor

Approximately 70% of all spinal tumors are located on the thoracic spine with 85% of these tumors on the ventral surface of the vertebral body and epidural space.^67,68 Current treatment options include surgery, radiation, and chemotherapy. Patchell and colleagues⁶⁹ found that significantly more patients treated with direct surgical decompression followed by radiation were able to walk after treatment than patients who were treated with radiotherapy alone. An anterior approach to this decompression offers the advantages of direct cord decompression with tumor resection, immediate interbody reconstruction and stabilization, and a lower wound complication rate than posterior incisions.⁶⁸ Although traditional open transthoracic vertebrectomies have been used, they are associated with significant morbidity.⁷⁰

Advances in endoscopic expandable interbody cages have made the excision and stabilization of these tumors possible through a thoracoscopic approach.^68,71 Thoracoscopy has been shown to have substantial clinical benefits in patients with tumors, including reduced postoperative pain, shorter intensive care unit and hospital stays, faster return to activity, and reduced complication rates.^68,71,72 These benefits are especially important because these patients have a mean survival of only 8 to 12 months.⁶⁸ Although data on large case series are pending, thoracoscopy is a promising treatment modality for these patients.

Trauma

In principle, the treatment of thoracic spinal injuries (e.g., burst fractures, multiple compression fractures, dislocations) involves correction of malposition, decompression of the spinal canal, and stabilization. To achieve these goals, anterior column reconstruction or decompression or both are often required. Because of the morbidity associated with conventional open thoracotomy, a thoracoscopic procedure has been developed to provide a less invasive solution. Although a thoracoscopic approach requires a longer operative time, it has been shown to have good clinical results in trauma patients with burst fractures. Beisse and colleagues⁷³ reported 371 patients who underwent thoracoscopic anterior reconstruction and fusion with instrumentation for spinal trauma. The average duration of surgery was 6 hours, and this gradually decreased to an average of 2.5 to 3 hours as the surgeon gained experience and skill. An 85% to 90% fusion rate was observed with the thoracoscopic technique, which Beisse and colleagues⁷³ believed was comparable with the standard approach.

Thoracic Disc Herniation

Surgical treatment is required for herniated discs that cause neurologic symptoms that are refractory to conservative care. Myelopathy is the strongest indication for surgery to prevent permanent damage to the spinal cord. Approaches for treatment of thoracic disc herniation include the posterior transpedicular approach, posterolateral approach, and anterior transthoracic approach (thoracotomy and thoracoscopy). The endoscope provides a magnified view of the entire ventral surface of the spine and spinal cord. Discectomy and rib head excision provide access to the spinal canal, which must be clearly visualized to ensure the decompression is complete. Anand and Regan⁷⁴ reported the outcome of 100 such cases performed endoscopically. These authors reported that thoracoscopic surgery for thoracic disc herniation has an overall long-term satisfaction rate of 84% and a clinical success rate of 70% for refractory thoracic disc disease.