- Email: [email protected]
Mini-open anterior approach for corpectomy in the thoracolumbar spine
Surgical Neurology 69 (2008) 25 – 32 www.surgicalneurology-online.com
Spine
Mini-open anterior approach for corpectomy in the thoracolumbar spine Michael Payer, MD4, Cyrille Sottas, MD Department of Neurosurgery, University Hospital of Geneva, 1211 Geneva 14, Switzerland Received 5 December 2006; accepted 24 January 2007
Abstract
Background: Traditional open anterior approaches to the TL spine were reported with a significant morbidity from a large wound field; therefore, bminimally invasiveQ thoracoscopic and laparoscopic anterior approaches have been recently introduced. However, these endoscopic techniques require a long and steep learning curve, require expensive disposable endoscopy material, and may be little suited for complication management. Alternatively, bmini-openQ anterior approaches with tablemounted retractor systems have also been recently introduced. Methods: Thirty-seven patients underwent a single-level thoracic or lumbar corpectomy and cage reconstruction for an unstable traumatic burst fracture or vertebral body tumor. A transthoracic (n = 6), transthoracic transdiaphragmatic (n = 23), or retroperitoneal (n = 8) mini-open approach was conducted with the SynFrame (Stratec Medical, Oberdorf, Switzerland) table-mounted retractor. Prior posterior pedicle screw fixation was performed in 35 of 37 patients. Results: The mean surgical duration of the anterior approach was 181 minutes, and the average blood loss was 632 mL. There was no neurological worsening. On a VAS from 0 to 10, the mean local pain from the anterior approach was 1.7 at 6 months postoperatively, 1.4 at 12 months, and 1.0 at 24 months. Construct stability was found in all patients at 6 months after surgery. Six transient complications occurred. Conclusions: The mini-open anterior approach for corpectomy in the TL spine is safe, reliable, and economical. The table-mounted SynFrame retractor provides a stable operating field through which a familiar direct 3-dimensional view of the anterior TL spine is obtained with limited approach morbidity. This technique is an excellent alternative to thoracoscopic or laparoscopic procedures, avoiding the steep learning curve, technical difficulties, and equipment costs of endoscopic procedures. D 2008 Elsevier Inc. All rights reserved.
Keywords:
Anterior approach; Retractor; Anterior column; Thoracolumbar spine; Corpectomy
1. Introduction The anterior approach to the thoracic and lumbar spine with corpectomy is a recognized treatment option for unstable burst fractures [21,23,26], vertebral body tumors [9], or vertebral osteomyelitis [12,22], combining the advantages of anterior decompression of the dural sac with biomechanical restoration of the compromised anterior load-
Abbreviations: ASIA, American Spinal Injury Association; CT, computed tomography; NASCIS, National Acute Spinal Cord Injury Study; TL, thoracolumbar; VAS, visual analogue scale. 4 Corresponding author. Tel.: +41 022 372 82 24; fax: +41 022 372 82 20. E-mail address: [email protected] (M. Payer). 0090-3019/$ – see front matter D 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2007.01.075
bearing column. The recent development of rigid corpectomy reconstruction cages has made the anterior approaches to the TL spine even more attractive by improving the biomechanical strength of the anterior column support [24]. Traditional wide open anterior approaches to the TL spine were reported with a significant complication rate, intercostal neuralgia, and postthoracotomy pain being the main complaints [5,8,14]. Therefore, so-called minimally invasive thoracoscopic and laparoscopic anterior approaches to the TL spine have been introduced [2,4,11,25,27]; however, these techniques require a steep learning curve with prolonged surgical duration, require costly equipment, and can hardly be recommended for common use. Also recently, bmini-openQ approaches to the anterior TL spine have been successfully introduced with the use of a table-mounted
26
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
retractor system [1,13,19]. We report our technique and experience with the mini-open anterior approach in a consecutive series of 37 patients with thoracic and lumbar corpectomies, using the table-mounted SynFrame (Stratec Medical, Oberdorf, Switzerland) retractor. 2. Material and methods 2.1. Patients Thirty-nine consecutive patients underwent a single-level corpectomy for traumatic burst fracture or tumor. Two trauma patients were lost to follow-up; altogether, 37 patients—15 women and 22 men, with a mean age of 42 years (19-75 years)—could be included in this study (Table 1). An unstable traumatic single-level burst fracture was present in 26 cases and an unstable tumor in 11 cases; 15 of the 26 fracture cases have recently been included in a different study [23]. Instability of a traumatic burst fracture was defined as the presence of at least one of the following criteria: a neurological deficit, more than 208 of regional kyphosis, at least 50% loss of anterior vertebral body height, and/or significant posterior element lesion. A vertebral tumor was considered unstable in case of a pathological fracture, 2or 3-column involvement according to the 3-column concept by Denis [6], or anterior neural compression. None of the
Table 1 Patient overview Patients: Mean age (y): Pathology type:
37 patients; 22 men, 15 women 42 (19-75) Fracture 26 patients –17 type A3 fractures –5 type B fractures with burst –4 type C fractures with burst
Pathology level and approach: T5-T11 Transthoracic approach
T12-L2
Transthoracic transdiaphragmatic approach
L3-L4
Retroperitoneal approach
Tumor 11 patients –3 breast carcinoma metastases –2 renal carcinoma metastases –2 multiple myelomas –2 liver carcinoma metastases –1 lung adenocarcinoma metastasis –1 aneurysmal bone cyst 6 patients (1 fracture, 5 tumors) –T6: 2 patients –T9: 1 patient –T10: 1 patient –T11: 2 patients 23 patients (20 fractures, 3 tumors) –T12: 5 patients –L1: 15 patients –L2: 3 patients 8 patients (5 fractures, 3 tumors) –L3: 6 patients –L4: 2 patients
Table 2 Standard neurological classification of spinal cord injury according to ASIA (ASIA impairment scale) A. Complete spinal cord injury: No motor or sensory function is preserved in the sacral segments S4-S5. B. Incomplete spinal cord injury: Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5. C. Incomplete spinal cord injury: Motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3. D. Incomplete spinal cord injury: Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more. E. Normal : Motor and sensory function is normal.
patients in this study had manifest spinal osteoporosis, infection, or inflammatory disease of the spine. Neurologically, the patients were classified according to the ASIA classification [17] (Table 2). All patients with a neurological deficit from trauma had received intravenous steroids preoperatively according to the NASCIS II protocol [3]; 7 of 11 tumor patients had received steroids because of preoperative neurological deficit. Postoperative pain at the anterior approach site was evaluated on a VAS from 0 to 10. In all trauma patients and in 9 of the 11 tumor patients, a posterior transpedicular fixation from the vertebra above the lesion to the vertebra below the lesion was performed as a first surgical step, correcting the kyphotic deformity and assuring posterior stabilization; the anterior approach was then performed as a staged procedure 7 to 10 days after the posterior procedure in traumatic fractures and as a singlestage procedure in the tumor cases, without anterolateral plating. In the 2 patients with a tumor not involving the posterior elements, a single anterior approach was performed with anterolateral plating. 2.2. The SynFrame retractor The SynFrame retractor is an adjustable ring that is fixed by one arm on each side of the operating table, giving surgical access to any point around the ring, and has been previously described [1,13] (Fig. 1). It assures permanent stability of the surgical field, enabling a small access to the anterior spine through the thorax or the retroperitoneum. Blades from 6 to 16 cm in length are to be clicked onto the ring at any point along the ring and can be adjusted individually in all 3 planes. In the current series, one or two blades were installed medially, one cranially, one laterally, and one caudally. Alternatively, the SynFrame system also offers the use of modified Hohmann levers, which have not been used in this series. 2.3. Surgical technique For corpectomies between T5 and T10, a right-sided approach was used; and for corpectomies between T11 and L4, a left-sided approach was used, except in tumor cases,
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Fig. 1. View of the SynFrame with retractor blades clicked onto the ring; the retractor blades can be adjusted individually in all 3 planes.
where the approach was conducted from the more involved side. After intubation, the patient is positioned in a true lateral position. The surgeon stands on the posterior side of the patient, and one assistant is required on the ventral side of the patient. The patients with thoracotomy were intubated with a double-lumen tubus, and the lung at the side of approach was partially deflated by the anesthesiologist after rib removal. 2.4. Transthoracic approach for corpectomy between T5 and T11 An oblique 6- to 10-cm incision is made over the rib one or two levels higher than the corpectomy level. After subperiosteal exposure, sparing the intercostal nerve and vessels along the caudal edge of the rib, approximately 10 cm of the rib is removed and the ipsilateral lung is partially deflated. The parietal pleura is opened parallel to the rib direction, and the lung is pushed medially with wet towels. The pathological vertebra is often recognized by the overlying hematoma in fractures and by tumor bulging in metastases and confirmed by lateral fluoroscopy. The SynFrame retractor is now inserted. The parietal pleura is opened in a sagittal direction over the lateral convexity of the pathological vertebra, and the corpectomy and its reconstruction can now be performed. 2.5. Transthoracic transdiaphragmatic approach for corpectomy between T12 and L2 A 6- to 10-cm incision is made over the 10th rib on the left lateral convexity of the thoracic wall. After subperiosteal exposure, approximately 10 cm of the rib is removed and the ipsilateral lung is partially deflated. The parietal pleura is opened parallel to the rib direction, and the lung is pushed cranially with wet towels. At this stage, the left lateral convexity of the diaphragm becomes exposed. The SynFrame retractor is now inserted with relatively short blades.
27
The diaphragm is opened along the thoracic wall, leaving a 2-cm rim laterally, with traction sutures every 2 to 3 cm to facilitate later closure. Under traction with surgical forceps, the outer fascia and the muscular layer of the diaphragm are incised with a monopolar electrode in an anteroposterior direction up to the lateral convexity of the spine, which can be well palpated. Great care has to be taken to stay in a safe distance from the perivascular layers of the abdominal aorta. The inner fascia of the diaphragm is now opened by blunt dissection with scissors under traction with surgical forceps, and the peritoneum is pushed medially away from the diaphragm with cottonoids. At this stage, longer SynFrame blades are inserted to retract the peritoneal sac medially, exposing the anterolateral convexity of the spine (Fig. 2B). The parietal pleura is opened in a sagittal direction over the lateral convexity of the lower thoracic spine, and the psoas muscle is pushed laterally with a Cobb elevator in the upper lumbar spine. The lateral convexity of the spine is exposed in a subperiosteal fashion. After verifying the correct level under lateral fluoroscopy and adapting the position of the SynFrame blades, the corpectomy and its reconstruction can now be performed. 2.6. Retroperitoneal approach for corpectomy at L3 and L4 A 6- to 10-cm horizontal incision is made from the tip of the 12th rib toward the ipsilateral rectus abdominis muscle. The oblique external and internal muscles with their fascia are opened along their fibers, as is subsequently the transversus abdominis muscle. The transversus abdominis fascia is now incised carefully from lateral to medial under traction with surgical forceps. The underlying peritoneum is pushed posteriorly away from the transverse abdominis fascia with cottonoids, thus opening the retroperitoneal space. Further medial retraction of the peritoneal sac exposes the quadratus lumborum muscle laterally and the psoas muscle medially. The SynFrame retractor is now inserted. Two medial blades retract the peritoneal sac medially, one blade retracts the rib cage cranially, and one blade retracts the abdominal muscles caudally. The ureter may be identified anterior to the psoas muscle and should be retracted medially together with the peritoneum. Various nerves of the lumbar plexus may be visualized and should be preserved: the ilioinguinal nerve on the anterior surface of the psoas muscle, the iliohypogastric nerve between the psoas and quadratus lumborum muscle, and the subcostal nerve on the anterior surface of the quadratus lumborum muscle. The psoas muscle is pushed laterally with a Cobb elevator, giving subperiosteal exposure of the lateral convexity of the spine; a lateral blade pulls the psoas muscle laterally. If the psoas muscle is very thick as in athletic patients, it can be split sagittally along its fibers before the bulk of the muscle can be retracted laterally. It is important to adjust the SynFrame blades throughout the preparation to focalize the access to the corpectomy vertebra and to protect the vessels and
28
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Fig. 2. Illustrative example of a fracture case: 23-year-old man with unstable burst fracture at L1 after a skiing accident. A: Preoperative sagittal CT reconstruction. B: Intraoperative photograph after left-sided transthoracic transdiaphragmatic approach, L1 corpectomy, and cage reconstruction. The SynFrame retractor pulls the rib cage and abdominal contents medially; the lateral retractor blade has been removed for better overview. C: Picture of the patient’s anterior and posterior wound. D: Lateral radiograph at 12 months postoperatively.
visceral organs. After verifying the correct level under lateral fluoroscopy, the corpectomy and its reconstruction can now be performed. 2.7. Corpectomy and reconstruction The segmental vessels of the corpectomy vertebra are ligated and divided. The disc above and below the corpectomy level is removed, clearing the endplates of all cartilage while preserving the cortical part of the
endplates. Disc removal is avascular and should therefore precede the corpectomy. In case of a traumatic fracture, a subtotal corpectomy of the fractured vertebral body is performed, leaving the contralateral and anterior vertebral body wall in place. In case of a neurological deficit, the posterior wall is also removed to expose the dura. In case of a tumor, the corpectomy should be as complete as possible, leaving only the cortical anterior and contralateral vertebral body wall behind.
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
For corpectomy reconstruction in this series, an expandable titanium cage (VBR, Ulrich, Ulm, Germany) was used in all patients, 20 or 24 mm in diameter and filled and surrounded with cancellous bone from the corpectomy in trauma cases and granules of bone substitute in tumor cases. The cage is progressively distracted to engage well into the vertebral endplates and then locked (Fig. 2B). 2.8. Closure After thorough wound washout, the SynFrame retractor is removed. The opened diaphragm is closed with a continuous suture in a posterior-anterior direction, leaving a 1- to 2-cm small gap posteriorly over the spine to enable blood flow from the corpectomy into the costodiaphragmatic recess. After thoracotomy, 2 thoracic drains are inserted from the anterior axillary line: one is placed posteriorly into the costodiaphragmatic recess for blood drainage, the other one anteriorly toward the pulmonary apex for air drainage. The ribs above and below the thoracotomy are approximated with 2 thick nonresorbable sutures. The ipsilateral lung is now expanded by the anesthesiologist; and muscles, subcutaneous layer, and skin are separately adapted by running sutures. After a retroperitoneal approach, a large suction drain is inserted over the corpectomy; and muscles, subcutaneous layer, and skin are separately adapted by running sutures. 2.9. Postoperative management The patients were usually mobilized on the second postoperative day. No brace was given. The thoracic drains were removed between the first and fourth postoperative day, when less than 200 mL of fluid was collected over 24 hours; retroperitoneal suction drains were removed 24 hours after surgery. The patients were prospectively observed clinically and with plain lateral and anteroposterior radiographs at 3, 6, 12,
29
and 24 months postoperatively. Clinical observation consisted of neurological grading according to the ASIA classification and pain evaluation on a VAS from 0 to 10 for pain in the anterior approach site. No hardware removal was performed in any of the patients. 3. Results All fracture patients and 6 tumor patients reached the 24month follow-up, 4 tumor patients reached the 12-month follow-up, and 1 tumor patient died after the 6-month follow-up. 3.1. Surgical results The mean surgical duration of the anterior approach for all patients was 181 minutes (range, 120-253), with a mean of 178 minutes for the fracture patients and 188 minutes for the tumor patients. The mean surgical duration was 178 minutes in the subgroup of 6 patients with a transthoracic approach, also 178 minutes in the subgroup of 23 patients with a transthoracic transdiaphragmatic approach, and 191 minutes in the subgroup of 8 patients with a retroperitoneal approach. The average blood loss from the anterior approach for all patients was 632 mL (range, 350-2000), with a mean of 598 mL for the fracture patients and 711 mL for the tumor patients. The mean blood loss was 535 mL in the subgroup of the transthoracic approach, 644 mL in the subgroup of the transthoracic transdiaphragmatic approach, and 670 mL in the subgroup of the retroperitoneal approach. 3.2. Radiological results Because bony fusion of a titanium corpectomy cage cannot be reliably assessed on plain radiographs or CT, construct stability was defined in the current series as absence of progressive kyphosis, absence of hardware
Fig. 3. Illustrative example of a tumor case: 67-year-old woman with an unstable T12 metastasis from breast carcinoma. A: Preoperative sagittal CT reconstruction. B: Lateral radiograph at 12 months postoperatively. C: Anteroposterior radiograph at 12 months postoperatively.
30
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Table 3 Average pain on a VAS (0 = minimum, 10 = maximum) from the anterior approach All patients Transthoracic approach Transthoracic transdiaphragmatic approach Retroperitoneal approach
6 mo 1.7 (0-5) 2.5 (0-5) 1.7 (0-3)
12 mo 1.4 (0-6) 2.3 (0-6) 1.1 (0-3)
24 mo 1.0 (0-3) 0.5 (0-1) 1.1 (0-3)
1.1 (0-2)
1.6 (0-3)
0.6 (0-1)
failure, and absence of radiolucencies at the screw-bone or cage-bone interface. Partial loss of kyphosis correction was frequently observed within the first 6 months postoperatively, without any further change thereafter. Altogether, construct stability was found in all patients after 6 months after surgery; and no patient had to be reoperated. Figs. 2 and 3 show illustrative examples. 3.3. Clinical results Mean local pain for all patients from the anterior approach was 1.7 (range, 0-5) at 6 months postoperatively, 1.4 (range, 0-6) at 12 months, and 1.0 (range, 0-3) at 24 months (Table 3). Neurologically, all 15 intact patients (ASIA E) remained so during the observation period; and 20 of 22 patients with a preoperative deficit recovered partially, whereas 2 patients showed no recovery. There was no case of neurological worsening postoperatively. 3.4. Complications There were 6 perioperative complications from the anterior approach. One tumor patient had a small dural tear after a T6 corpectomy; fibrin glue and muscle patch were applied, chest tubes were kept without suction, and 4 days of bed rest led to uneventful healing. One patient developed a progressive anterior pneumothorax with dyspnea within 3 hours postoperatively despite the 2 thoracic drains, one of which was positioned too posteriorly and was malfunctioning. A third thoracic drain had to be inserted, and the patient recovered well. One patient had a transient paralytic ileus for 1 week postoperatively. One patient had persistent ilioinguinal hypesthesia after the anterior surgery, and one patient had transient ilioinguinal hypesthesia for 6 weeks; compression of the ilioinguinal nerve from retraction of the psoas muscle might be responsible for this complication. One tumor patient had a superficial wound infection. 4. Discussion There is an ongoing debate on the advantages and disadvantages of open vs endoscopic approaches to the anterior TL spine in terms of access morbidity, complications and complication management, surgical duration, length of stay, and costs. Wide open anterior approaches for corpectomy in the thoracic or lumbar spine may cause significant pain from a large wound field, especially intercostal neuralgia and postthoracotomy pain [5,8,14]; therefore, minimally invasive endoscopic approaches have been introduced in
the late 1990s [2,11,25]. However, one prospective study compared open thoracotomy with thoracoscopy and showed equal incidence and intensity of persistent postthoracotomy pain [10]. Furthermore, endoscopic procedures are usually unfamiliar to the spine surgeon and require a long learning curve. The 2-dimensional endoscopic view may cause disorientation in relation to the anatomical topography due to magnification and lack of physical verification by the surgeon, which may be responsible for the reported serious endoscopic complications [15,20]. Although minimally invasive, endoscopic interventions may become even more harmful to the patient than open procedures [13]. Therefore, the initial enthusiasm for endoscopic anterior spinal procedures has drifted toward the use of a less invasive but open approach to the anterior lumbar spine, called a mini-open approach with skin incision lengths between 4 and 12 cm [1,7,13,16,19]. Although it still reduces access morbidity, such a mini-open anterior approach gives a familiar direct 3dimensional view of the spine, which is particularly helpful and safe for the preparation of vessels, nerves, and visceral structures. Under direct view, the management of vascular complications is quicker and easier compared with endoscopic procedures, which frequently have to be converted into open procedures in such cases [11,18]. Furthermore, a direct 3-dimensional view facilitates considerably the corpectomy with or without spinal canal clearance as well as the cage or graft insertion, reducing surgical duration [13,19]. Though comparing surgical times of different techniques is of little value in different series with different surgeons, Kossman reported significantly shorter operating times for corpectomy and anterior reconstruction in the TL spine through his mini-open approach [13] compared with endoscopic approaches [4,25]. Similarly, Muhlbauer et al report encouraging initial experience with an open minimally invasive retroperitoneal approach in 5 corpectomy cases, using a different but comparable self-retaining retractor [19]. In economical terms, reduced costs from potentially shorter length of hospital stay after endoscopic procedures have to be weighed against the higher costs from potentially prolonged surgical duration and against the cost of investing in endoscopic instruments and disposable materials. In contrast to a traditional setup for open anterior TL spine surgery with one surgeon and two assistants [8], only one surgeon with a single assistant, as for endoscopic procedures, is required for a mini-open anterior approach with a self-retaining retractor [13]. Although different pathologies, affected levels, and integration of learning curves make comparisons inexact, the mean surgical time of 181 minutes and blood loss of 632 mL from the open minimally invasive anterior approach in the current study compares favorably with endoscopic procedures [2,11,25,27]. Chronic postthoracotomy pain, defined as more than 3/10 on the VAS after 6 months postoperatively, was found in 5% of our cases at 12 months and lies in the lower range of the reported 4% to 35% for minimally invasive procedures [11]. So far, we have not
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
experienced serious complications such as vascular, visceral, or neurological damage. Altogether, the current study confirms the findings of other reports on mini-open anterior approaches to the TL spine with a self-retaining retractor [13,19]: The limited open anterior approach with the SynFrame retractor for corpectomy in the TL spine offers the advantage of a small open access with a permanent, stable operation field, which limits the approach morbidity, gives a familiar 3-dimensional open view to the anterior spinal anatomy, and as such facilitates the corpectomy and reconstruction procedure and potential complication management. 5. Conclusion The mini-open anterior approach for corpectomy in the TL spine is safe, reliable, and economical. The tablemounted SynFrame retractor provides a stable operating field through which a familiar direct 3-dimensional view of the anterior TL spine is obtained with limited approach morbidity. This technique is an excellent alternative to thoracoscopic or laparoscopic procedures, avoiding the steep learning curve, technical difficulties, and equipment costs of endoscopic procedures.
References [1] Aebi M, Steffen T. Synframe: a preliminary report. Eur Spine J 2000;(9 Suppl 1):S44-S50. [2] Beisse R. Endoscopic surgery on the thoracolumbar junction of the spine. Eur Spine J 2006;15(6):687 - 704. [3] Bracken MB, Shepard MJ, Collins WF, et al. A randomized, controlled trial of methylprednisolone or naloxone in the treatment of acute spinal-cord injury. Results of the Second National Acute Spinal Cord Injury Study. N Engl J Med 1990;322(20):1405 - 11. [4] Bqhren V, Beisse R, Potulski M. Minimally invasive ventral spondylodesis for injuries of the thoracic and lumbar spine. Chirurgie 1997;68:1076 - 84. [5] Dajczman E, Gordon A, Kreisman H, et al. Long-term postthoracotomy pain. Chest 1991;99:270 - 3. [6] Denis F. The three-column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983;8(8):817 - 31. [7] DeWald CJ, Millikan KW, Hammerberg KW, et al. An open, minimally invasive approach to the lumbar spine. Am Surg 1999;65:61 - 8. [8] Faciszewski T, Winter RB, Lonstein JE, et al. The surgical and medical perioperative complications of anterior spinal fusion surgery in the thoracic and lumbar spine in adults. Spine 1995;20:1592 - 9. [9] Fourney D, Gokaslan Z. Anterior approaches for thoracolumbar metastatic spine tumors. Neurosurg Clin N Am 2004;15(4):443 - 51. [10] Furrer M, Rechsteiner R, Eigenmann V, et al. Thoracotomy and thoracoscopy: postoperative pulmonary function, pain and chest wall complaints. Eur J Cardiothorac Surg 1997;12(1):82 - 7. [11] Kim D, Jahng T, Balabhadra R, et al. Thoracoscopic transdiaphragmatic approach to thoracolumbar junction fractures. Spine J 2004;4(3):317 - 28. [12] Korovessis P, Petsinis G, Koureas G, et al. Anterior surgery with insertion of titanium mesh cage and posterior instrumented fusion performed sequentially on the same day under one anesthesia for septic spondylitis of thoracolumbar spine: is the use of titanium mesh cages safe? Spine 2006;31(9):1014 - 9.
31
[13] Kossmann T, Jacobi D, Trentz O. The use of a retractor system (SynFrame) for open, minimal invasive reconstruction of the anterior column of the thoracic and lumbar spine. Eur Spine J 2001;10(5): 396 - 402. [14] Landreneau R, Hazelrigg S, Mack M. Postoperative pain-related morbidity. Video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56:1284 - 9. [15] Matthews HH, Evans MT, Molligan HJ, et al. Laparoscopic discectomy with anterior interbody fusion: a preliminary review. Spine 1995;20:1797 - 802. [16] Mayer H. A new microsurgical technique for minimal invasive anterior lumbar interbody fusion. Spine 1997;22:691 - 700. [17] Maynard Jr FM, Bracken MB, Creasey G, et al. International standards for neurological and functional classification of spinal cord injury. Spinal Cord 1997;35:266 - 74. [18] McAfee P, Regan J, Zdeblick T, et al. The incidence of complications in endoscopic anterior thoracolumbar spinal reconstructive surgery. A prospective multicenter study comprising the first 100 consecutive cases. Spine 1995;20(14):1624 - 32. [19] Muhlbauer M, Pfisterer W, Eyb R, et al. Minimally invasive retroperitoneal approach for lumbar corpectomy and anterior reconstruction. Technical noteJ Neurosurg 2000;93(1 Suppl):161 - 7. [20] Olsen D, McCord D, Law M. Laparoscopic discectomy with anterior interbody fusion of L5-S1. Surg Endosc 1996;10:1158 - 63. [21] Oskouian R, Shaffrey C, Whitehill R, et al. Anterior stabilization of three-column thoracolumbar spinal trauma. J Neurosurg Spine 2006;5(1):18 - 25. [22] Pappou I, Papadopoulos E, Swanson A, et al. Pott disease in the thoracolumbar spine with marked kyphosis and progressive paraplegia necessitating posterior vertebral column resection and anterior reconstruction with a cage. Spine 2006;31(4):E123 - 7. [23] Payer M. Immediate open anterior reduction and antero-posterior fixation/fusion for bilateral cervical locked facets. Acta Neurochir (Wien) 2005;147(5):509 - 13. [24] Pflugmacher R, Schleicher P, Schaefer J, et al. Biomechanical comparison of expandable cages for vertebral body replacement in the thoracolumbar spine. Spine 2004;29(13):1413 - 9. [25] Regan JJ, Guyer RD. Endoscopic techniques in spinal surgery. Clin Orthop 1997;335:122 - 39. [26] Sasso R, Renkens K, Hanson D, et al. Unstable thoracolumbar burst fractures: anterior-only versus short-segment posterior fixation. J Spinal Disord Tech 2006;19(4):242 - 8. [27] Visocchi M, Masferrer R, Sonntag V, et al. Thoracoscopic approaches to the thoracic spine. Acta Neurochir 1998;140(8):737 - 43.
Commentary This is a well-written article emphasizing the advantages of the mini-open anterior approach to the thoracolumbar spine in cases of unstable vertebral body fracture or vertebral body tumour. The SynFrame retractor allows sufficiently good override control of the operative field. Endoscopic procedures allow shorter stay in hospital with an ensuing lower cost. However, the mini-open procedure is probably safer: reconstruction procedure (cage instrumentation and plating) and treatment of possible complication are easier than by the endoscopic technique, which, in the case of intraoperative complication, sometimes requires an immediate subsequent open procedure. In all the traumatic lesions of this series, a combined 2stage procedure has been used: posterior transpedicular
Spine
Mini-open anterior approach for corpectomy in the thoracolumbar spine Michael Payer, MD4, Cyrille Sottas, MD Department of Neurosurgery, University Hospital of Geneva, 1211 Geneva 14, Switzerland Received 5 December 2006; accepted 24 January 2007
Abstract
Background: Traditional open anterior approaches to the TL spine were reported with a significant morbidity from a large wound field; therefore, bminimally invasiveQ thoracoscopic and laparoscopic anterior approaches have been recently introduced. However, these endoscopic techniques require a long and steep learning curve, require expensive disposable endoscopy material, and may be little suited for complication management. Alternatively, bmini-openQ anterior approaches with tablemounted retractor systems have also been recently introduced. Methods: Thirty-seven patients underwent a single-level thoracic or lumbar corpectomy and cage reconstruction for an unstable traumatic burst fracture or vertebral body tumor. A transthoracic (n = 6), transthoracic transdiaphragmatic (n = 23), or retroperitoneal (n = 8) mini-open approach was conducted with the SynFrame (Stratec Medical, Oberdorf, Switzerland) table-mounted retractor. Prior posterior pedicle screw fixation was performed in 35 of 37 patients. Results: The mean surgical duration of the anterior approach was 181 minutes, and the average blood loss was 632 mL. There was no neurological worsening. On a VAS from 0 to 10, the mean local pain from the anterior approach was 1.7 at 6 months postoperatively, 1.4 at 12 months, and 1.0 at 24 months. Construct stability was found in all patients at 6 months after surgery. Six transient complications occurred. Conclusions: The mini-open anterior approach for corpectomy in the TL spine is safe, reliable, and economical. The table-mounted SynFrame retractor provides a stable operating field through which a familiar direct 3-dimensional view of the anterior TL spine is obtained with limited approach morbidity. This technique is an excellent alternative to thoracoscopic or laparoscopic procedures, avoiding the steep learning curve, technical difficulties, and equipment costs of endoscopic procedures. D 2008 Elsevier Inc. All rights reserved.
Keywords:
Anterior approach; Retractor; Anterior column; Thoracolumbar spine; Corpectomy
1. Introduction The anterior approach to the thoracic and lumbar spine with corpectomy is a recognized treatment option for unstable burst fractures [21,23,26], vertebral body tumors [9], or vertebral osteomyelitis [12,22], combining the advantages of anterior decompression of the dural sac with biomechanical restoration of the compromised anterior load-
Abbreviations: ASIA, American Spinal Injury Association; CT, computed tomography; NASCIS, National Acute Spinal Cord Injury Study; TL, thoracolumbar; VAS, visual analogue scale. 4 Corresponding author. Tel.: +41 022 372 82 24; fax: +41 022 372 82 20. E-mail address: [email protected] (M. Payer). 0090-3019/$ – see front matter D 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2007.01.075
bearing column. The recent development of rigid corpectomy reconstruction cages has made the anterior approaches to the TL spine even more attractive by improving the biomechanical strength of the anterior column support [24]. Traditional wide open anterior approaches to the TL spine were reported with a significant complication rate, intercostal neuralgia, and postthoracotomy pain being the main complaints [5,8,14]. Therefore, so-called minimally invasive thoracoscopic and laparoscopic anterior approaches to the TL spine have been introduced [2,4,11,25,27]; however, these techniques require a steep learning curve with prolonged surgical duration, require costly equipment, and can hardly be recommended for common use. Also recently, bmini-openQ approaches to the anterior TL spine have been successfully introduced with the use of a table-mounted
26
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
retractor system [1,13,19]. We report our technique and experience with the mini-open anterior approach in a consecutive series of 37 patients with thoracic and lumbar corpectomies, using the table-mounted SynFrame (Stratec Medical, Oberdorf, Switzerland) retractor. 2. Material and methods 2.1. Patients Thirty-nine consecutive patients underwent a single-level corpectomy for traumatic burst fracture or tumor. Two trauma patients were lost to follow-up; altogether, 37 patients—15 women and 22 men, with a mean age of 42 years (19-75 years)—could be included in this study (Table 1). An unstable traumatic single-level burst fracture was present in 26 cases and an unstable tumor in 11 cases; 15 of the 26 fracture cases have recently been included in a different study [23]. Instability of a traumatic burst fracture was defined as the presence of at least one of the following criteria: a neurological deficit, more than 208 of regional kyphosis, at least 50% loss of anterior vertebral body height, and/or significant posterior element lesion. A vertebral tumor was considered unstable in case of a pathological fracture, 2or 3-column involvement according to the 3-column concept by Denis [6], or anterior neural compression. None of the
Table 1 Patient overview Patients: Mean age (y): Pathology type:
37 patients; 22 men, 15 women 42 (19-75) Fracture 26 patients –17 type A3 fractures –5 type B fractures with burst –4 type C fractures with burst
Pathology level and approach: T5-T11 Transthoracic approach
T12-L2
Transthoracic transdiaphragmatic approach
L3-L4
Retroperitoneal approach
Tumor 11 patients –3 breast carcinoma metastases –2 renal carcinoma metastases –2 multiple myelomas –2 liver carcinoma metastases –1 lung adenocarcinoma metastasis –1 aneurysmal bone cyst 6 patients (1 fracture, 5 tumors) –T6: 2 patients –T9: 1 patient –T10: 1 patient –T11: 2 patients 23 patients (20 fractures, 3 tumors) –T12: 5 patients –L1: 15 patients –L2: 3 patients 8 patients (5 fractures, 3 tumors) –L3: 6 patients –L4: 2 patients
Table 2 Standard neurological classification of spinal cord injury according to ASIA (ASIA impairment scale) A. Complete spinal cord injury: No motor or sensory function is preserved in the sacral segments S4-S5. B. Incomplete spinal cord injury: Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5. C. Incomplete spinal cord injury: Motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3. D. Incomplete spinal cord injury: Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more. E. Normal : Motor and sensory function is normal.
patients in this study had manifest spinal osteoporosis, infection, or inflammatory disease of the spine. Neurologically, the patients were classified according to the ASIA classification [17] (Table 2). All patients with a neurological deficit from trauma had received intravenous steroids preoperatively according to the NASCIS II protocol [3]; 7 of 11 tumor patients had received steroids because of preoperative neurological deficit. Postoperative pain at the anterior approach site was evaluated on a VAS from 0 to 10. In all trauma patients and in 9 of the 11 tumor patients, a posterior transpedicular fixation from the vertebra above the lesion to the vertebra below the lesion was performed as a first surgical step, correcting the kyphotic deformity and assuring posterior stabilization; the anterior approach was then performed as a staged procedure 7 to 10 days after the posterior procedure in traumatic fractures and as a singlestage procedure in the tumor cases, without anterolateral plating. In the 2 patients with a tumor not involving the posterior elements, a single anterior approach was performed with anterolateral plating. 2.2. The SynFrame retractor The SynFrame retractor is an adjustable ring that is fixed by one arm on each side of the operating table, giving surgical access to any point around the ring, and has been previously described [1,13] (Fig. 1). It assures permanent stability of the surgical field, enabling a small access to the anterior spine through the thorax or the retroperitoneum. Blades from 6 to 16 cm in length are to be clicked onto the ring at any point along the ring and can be adjusted individually in all 3 planes. In the current series, one or two blades were installed medially, one cranially, one laterally, and one caudally. Alternatively, the SynFrame system also offers the use of modified Hohmann levers, which have not been used in this series. 2.3. Surgical technique For corpectomies between T5 and T10, a right-sided approach was used; and for corpectomies between T11 and L4, a left-sided approach was used, except in tumor cases,
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Fig. 1. View of the SynFrame with retractor blades clicked onto the ring; the retractor blades can be adjusted individually in all 3 planes.
where the approach was conducted from the more involved side. After intubation, the patient is positioned in a true lateral position. The surgeon stands on the posterior side of the patient, and one assistant is required on the ventral side of the patient. The patients with thoracotomy were intubated with a double-lumen tubus, and the lung at the side of approach was partially deflated by the anesthesiologist after rib removal. 2.4. Transthoracic approach for corpectomy between T5 and T11 An oblique 6- to 10-cm incision is made over the rib one or two levels higher than the corpectomy level. After subperiosteal exposure, sparing the intercostal nerve and vessels along the caudal edge of the rib, approximately 10 cm of the rib is removed and the ipsilateral lung is partially deflated. The parietal pleura is opened parallel to the rib direction, and the lung is pushed medially with wet towels. The pathological vertebra is often recognized by the overlying hematoma in fractures and by tumor bulging in metastases and confirmed by lateral fluoroscopy. The SynFrame retractor is now inserted. The parietal pleura is opened in a sagittal direction over the lateral convexity of the pathological vertebra, and the corpectomy and its reconstruction can now be performed. 2.5. Transthoracic transdiaphragmatic approach for corpectomy between T12 and L2 A 6- to 10-cm incision is made over the 10th rib on the left lateral convexity of the thoracic wall. After subperiosteal exposure, approximately 10 cm of the rib is removed and the ipsilateral lung is partially deflated. The parietal pleura is opened parallel to the rib direction, and the lung is pushed cranially with wet towels. At this stage, the left lateral convexity of the diaphragm becomes exposed. The SynFrame retractor is now inserted with relatively short blades.
27
The diaphragm is opened along the thoracic wall, leaving a 2-cm rim laterally, with traction sutures every 2 to 3 cm to facilitate later closure. Under traction with surgical forceps, the outer fascia and the muscular layer of the diaphragm are incised with a monopolar electrode in an anteroposterior direction up to the lateral convexity of the spine, which can be well palpated. Great care has to be taken to stay in a safe distance from the perivascular layers of the abdominal aorta. The inner fascia of the diaphragm is now opened by blunt dissection with scissors under traction with surgical forceps, and the peritoneum is pushed medially away from the diaphragm with cottonoids. At this stage, longer SynFrame blades are inserted to retract the peritoneal sac medially, exposing the anterolateral convexity of the spine (Fig. 2B). The parietal pleura is opened in a sagittal direction over the lateral convexity of the lower thoracic spine, and the psoas muscle is pushed laterally with a Cobb elevator in the upper lumbar spine. The lateral convexity of the spine is exposed in a subperiosteal fashion. After verifying the correct level under lateral fluoroscopy and adapting the position of the SynFrame blades, the corpectomy and its reconstruction can now be performed. 2.6. Retroperitoneal approach for corpectomy at L3 and L4 A 6- to 10-cm horizontal incision is made from the tip of the 12th rib toward the ipsilateral rectus abdominis muscle. The oblique external and internal muscles with their fascia are opened along their fibers, as is subsequently the transversus abdominis muscle. The transversus abdominis fascia is now incised carefully from lateral to medial under traction with surgical forceps. The underlying peritoneum is pushed posteriorly away from the transverse abdominis fascia with cottonoids, thus opening the retroperitoneal space. Further medial retraction of the peritoneal sac exposes the quadratus lumborum muscle laterally and the psoas muscle medially. The SynFrame retractor is now inserted. Two medial blades retract the peritoneal sac medially, one blade retracts the rib cage cranially, and one blade retracts the abdominal muscles caudally. The ureter may be identified anterior to the psoas muscle and should be retracted medially together with the peritoneum. Various nerves of the lumbar plexus may be visualized and should be preserved: the ilioinguinal nerve on the anterior surface of the psoas muscle, the iliohypogastric nerve between the psoas and quadratus lumborum muscle, and the subcostal nerve on the anterior surface of the quadratus lumborum muscle. The psoas muscle is pushed laterally with a Cobb elevator, giving subperiosteal exposure of the lateral convexity of the spine; a lateral blade pulls the psoas muscle laterally. If the psoas muscle is very thick as in athletic patients, it can be split sagittally along its fibers before the bulk of the muscle can be retracted laterally. It is important to adjust the SynFrame blades throughout the preparation to focalize the access to the corpectomy vertebra and to protect the vessels and
28
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Fig. 2. Illustrative example of a fracture case: 23-year-old man with unstable burst fracture at L1 after a skiing accident. A: Preoperative sagittal CT reconstruction. B: Intraoperative photograph after left-sided transthoracic transdiaphragmatic approach, L1 corpectomy, and cage reconstruction. The SynFrame retractor pulls the rib cage and abdominal contents medially; the lateral retractor blade has been removed for better overview. C: Picture of the patient’s anterior and posterior wound. D: Lateral radiograph at 12 months postoperatively.
visceral organs. After verifying the correct level under lateral fluoroscopy, the corpectomy and its reconstruction can now be performed. 2.7. Corpectomy and reconstruction The segmental vessels of the corpectomy vertebra are ligated and divided. The disc above and below the corpectomy level is removed, clearing the endplates of all cartilage while preserving the cortical part of the
endplates. Disc removal is avascular and should therefore precede the corpectomy. In case of a traumatic fracture, a subtotal corpectomy of the fractured vertebral body is performed, leaving the contralateral and anterior vertebral body wall in place. In case of a neurological deficit, the posterior wall is also removed to expose the dura. In case of a tumor, the corpectomy should be as complete as possible, leaving only the cortical anterior and contralateral vertebral body wall behind.
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
For corpectomy reconstruction in this series, an expandable titanium cage (VBR, Ulrich, Ulm, Germany) was used in all patients, 20 or 24 mm in diameter and filled and surrounded with cancellous bone from the corpectomy in trauma cases and granules of bone substitute in tumor cases. The cage is progressively distracted to engage well into the vertebral endplates and then locked (Fig. 2B). 2.8. Closure After thorough wound washout, the SynFrame retractor is removed. The opened diaphragm is closed with a continuous suture in a posterior-anterior direction, leaving a 1- to 2-cm small gap posteriorly over the spine to enable blood flow from the corpectomy into the costodiaphragmatic recess. After thoracotomy, 2 thoracic drains are inserted from the anterior axillary line: one is placed posteriorly into the costodiaphragmatic recess for blood drainage, the other one anteriorly toward the pulmonary apex for air drainage. The ribs above and below the thoracotomy are approximated with 2 thick nonresorbable sutures. The ipsilateral lung is now expanded by the anesthesiologist; and muscles, subcutaneous layer, and skin are separately adapted by running sutures. After a retroperitoneal approach, a large suction drain is inserted over the corpectomy; and muscles, subcutaneous layer, and skin are separately adapted by running sutures. 2.9. Postoperative management The patients were usually mobilized on the second postoperative day. No brace was given. The thoracic drains were removed between the first and fourth postoperative day, when less than 200 mL of fluid was collected over 24 hours; retroperitoneal suction drains were removed 24 hours after surgery. The patients were prospectively observed clinically and with plain lateral and anteroposterior radiographs at 3, 6, 12,
29
and 24 months postoperatively. Clinical observation consisted of neurological grading according to the ASIA classification and pain evaluation on a VAS from 0 to 10 for pain in the anterior approach site. No hardware removal was performed in any of the patients. 3. Results All fracture patients and 6 tumor patients reached the 24month follow-up, 4 tumor patients reached the 12-month follow-up, and 1 tumor patient died after the 6-month follow-up. 3.1. Surgical results The mean surgical duration of the anterior approach for all patients was 181 minutes (range, 120-253), with a mean of 178 minutes for the fracture patients and 188 minutes for the tumor patients. The mean surgical duration was 178 minutes in the subgroup of 6 patients with a transthoracic approach, also 178 minutes in the subgroup of 23 patients with a transthoracic transdiaphragmatic approach, and 191 minutes in the subgroup of 8 patients with a retroperitoneal approach. The average blood loss from the anterior approach for all patients was 632 mL (range, 350-2000), with a mean of 598 mL for the fracture patients and 711 mL for the tumor patients. The mean blood loss was 535 mL in the subgroup of the transthoracic approach, 644 mL in the subgroup of the transthoracic transdiaphragmatic approach, and 670 mL in the subgroup of the retroperitoneal approach. 3.2. Radiological results Because bony fusion of a titanium corpectomy cage cannot be reliably assessed on plain radiographs or CT, construct stability was defined in the current series as absence of progressive kyphosis, absence of hardware
Fig. 3. Illustrative example of a tumor case: 67-year-old woman with an unstable T12 metastasis from breast carcinoma. A: Preoperative sagittal CT reconstruction. B: Lateral radiograph at 12 months postoperatively. C: Anteroposterior radiograph at 12 months postoperatively.
30
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
Table 3 Average pain on a VAS (0 = minimum, 10 = maximum) from the anterior approach All patients Transthoracic approach Transthoracic transdiaphragmatic approach Retroperitoneal approach
6 mo 1.7 (0-5) 2.5 (0-5) 1.7 (0-3)
12 mo 1.4 (0-6) 2.3 (0-6) 1.1 (0-3)
24 mo 1.0 (0-3) 0.5 (0-1) 1.1 (0-3)
1.1 (0-2)
1.6 (0-3)
0.6 (0-1)
failure, and absence of radiolucencies at the screw-bone or cage-bone interface. Partial loss of kyphosis correction was frequently observed within the first 6 months postoperatively, without any further change thereafter. Altogether, construct stability was found in all patients after 6 months after surgery; and no patient had to be reoperated. Figs. 2 and 3 show illustrative examples. 3.3. Clinical results Mean local pain for all patients from the anterior approach was 1.7 (range, 0-5) at 6 months postoperatively, 1.4 (range, 0-6) at 12 months, and 1.0 (range, 0-3) at 24 months (Table 3). Neurologically, all 15 intact patients (ASIA E) remained so during the observation period; and 20 of 22 patients with a preoperative deficit recovered partially, whereas 2 patients showed no recovery. There was no case of neurological worsening postoperatively. 3.4. Complications There were 6 perioperative complications from the anterior approach. One tumor patient had a small dural tear after a T6 corpectomy; fibrin glue and muscle patch were applied, chest tubes were kept without suction, and 4 days of bed rest led to uneventful healing. One patient developed a progressive anterior pneumothorax with dyspnea within 3 hours postoperatively despite the 2 thoracic drains, one of which was positioned too posteriorly and was malfunctioning. A third thoracic drain had to be inserted, and the patient recovered well. One patient had a transient paralytic ileus for 1 week postoperatively. One patient had persistent ilioinguinal hypesthesia after the anterior surgery, and one patient had transient ilioinguinal hypesthesia for 6 weeks; compression of the ilioinguinal nerve from retraction of the psoas muscle might be responsible for this complication. One tumor patient had a superficial wound infection. 4. Discussion There is an ongoing debate on the advantages and disadvantages of open vs endoscopic approaches to the anterior TL spine in terms of access morbidity, complications and complication management, surgical duration, length of stay, and costs. Wide open anterior approaches for corpectomy in the thoracic or lumbar spine may cause significant pain from a large wound field, especially intercostal neuralgia and postthoracotomy pain [5,8,14]; therefore, minimally invasive endoscopic approaches have been introduced in
the late 1990s [2,11,25]. However, one prospective study compared open thoracotomy with thoracoscopy and showed equal incidence and intensity of persistent postthoracotomy pain [10]. Furthermore, endoscopic procedures are usually unfamiliar to the spine surgeon and require a long learning curve. The 2-dimensional endoscopic view may cause disorientation in relation to the anatomical topography due to magnification and lack of physical verification by the surgeon, which may be responsible for the reported serious endoscopic complications [15,20]. Although minimally invasive, endoscopic interventions may become even more harmful to the patient than open procedures [13]. Therefore, the initial enthusiasm for endoscopic anterior spinal procedures has drifted toward the use of a less invasive but open approach to the anterior lumbar spine, called a mini-open approach with skin incision lengths between 4 and 12 cm [1,7,13,16,19]. Although it still reduces access morbidity, such a mini-open anterior approach gives a familiar direct 3dimensional view of the spine, which is particularly helpful and safe for the preparation of vessels, nerves, and visceral structures. Under direct view, the management of vascular complications is quicker and easier compared with endoscopic procedures, which frequently have to be converted into open procedures in such cases [11,18]. Furthermore, a direct 3-dimensional view facilitates considerably the corpectomy with or without spinal canal clearance as well as the cage or graft insertion, reducing surgical duration [13,19]. Though comparing surgical times of different techniques is of little value in different series with different surgeons, Kossman reported significantly shorter operating times for corpectomy and anterior reconstruction in the TL spine through his mini-open approach [13] compared with endoscopic approaches [4,25]. Similarly, Muhlbauer et al report encouraging initial experience with an open minimally invasive retroperitoneal approach in 5 corpectomy cases, using a different but comparable self-retaining retractor [19]. In economical terms, reduced costs from potentially shorter length of hospital stay after endoscopic procedures have to be weighed against the higher costs from potentially prolonged surgical duration and against the cost of investing in endoscopic instruments and disposable materials. In contrast to a traditional setup for open anterior TL spine surgery with one surgeon and two assistants [8], only one surgeon with a single assistant, as for endoscopic procedures, is required for a mini-open anterior approach with a self-retaining retractor [13]. Although different pathologies, affected levels, and integration of learning curves make comparisons inexact, the mean surgical time of 181 minutes and blood loss of 632 mL from the open minimally invasive anterior approach in the current study compares favorably with endoscopic procedures [2,11,25,27]. Chronic postthoracotomy pain, defined as more than 3/10 on the VAS after 6 months postoperatively, was found in 5% of our cases at 12 months and lies in the lower range of the reported 4% to 35% for minimally invasive procedures [11]. So far, we have not
M. Payer, C. Sottas / Surgical Neurology 69 (2008) 25 – 32
experienced serious complications such as vascular, visceral, or neurological damage. Altogether, the current study confirms the findings of other reports on mini-open anterior approaches to the TL spine with a self-retaining retractor [13,19]: The limited open anterior approach with the SynFrame retractor for corpectomy in the TL spine offers the advantage of a small open access with a permanent, stable operation field, which limits the approach morbidity, gives a familiar 3-dimensional open view to the anterior spinal anatomy, and as such facilitates the corpectomy and reconstruction procedure and potential complication management. 5. Conclusion The mini-open anterior approach for corpectomy in the TL spine is safe, reliable, and economical. The tablemounted SynFrame retractor provides a stable operating field through which a familiar direct 3-dimensional view of the anterior TL spine is obtained with limited approach morbidity. This technique is an excellent alternative to thoracoscopic or laparoscopic procedures, avoiding the steep learning curve, technical difficulties, and equipment costs of endoscopic procedures.
References [1] Aebi M, Steffen T. Synframe: a preliminary report. Eur Spine J 2000;(9 Suppl 1):S44-S50. [2] Beisse R. Endoscopic surgery on the thoracolumbar junction of the spine. Eur Spine J 2006;15(6):687 - 704. [3] Bracken MB, Shepard MJ, Collins WF, et al. A randomized, controlled trial of methylprednisolone or naloxone in the treatment of acute spinal-cord injury. Results of the Second National Acute Spinal Cord Injury Study. N Engl J Med 1990;322(20):1405 - 11. [4] Bqhren V, Beisse R, Potulski M. Minimally invasive ventral spondylodesis for injuries of the thoracic and lumbar spine. Chirurgie 1997;68:1076 - 84. [5] Dajczman E, Gordon A, Kreisman H, et al. Long-term postthoracotomy pain. Chest 1991;99:270 - 3. [6] Denis F. The three-column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983;8(8):817 - 31. [7] DeWald CJ, Millikan KW, Hammerberg KW, et al. An open, minimally invasive approach to the lumbar spine. Am Surg 1999;65:61 - 8. [8] Faciszewski T, Winter RB, Lonstein JE, et al. The surgical and medical perioperative complications of anterior spinal fusion surgery in the thoracic and lumbar spine in adults. Spine 1995;20:1592 - 9. [9] Fourney D, Gokaslan Z. Anterior approaches for thoracolumbar metastatic spine tumors. Neurosurg Clin N Am 2004;15(4):443 - 51. [10] Furrer M, Rechsteiner R, Eigenmann V, et al. Thoracotomy and thoracoscopy: postoperative pulmonary function, pain and chest wall complaints. Eur J Cardiothorac Surg 1997;12(1):82 - 7. [11] Kim D, Jahng T, Balabhadra R, et al. Thoracoscopic transdiaphragmatic approach to thoracolumbar junction fractures. Spine J 2004;4(3):317 - 28. [12] Korovessis P, Petsinis G, Koureas G, et al. Anterior surgery with insertion of titanium mesh cage and posterior instrumented fusion performed sequentially on the same day under one anesthesia for septic spondylitis of thoracolumbar spine: is the use of titanium mesh cages safe? Spine 2006;31(9):1014 - 9.
31
[13] Kossmann T, Jacobi D, Trentz O. The use of a retractor system (SynFrame) for open, minimal invasive reconstruction of the anterior column of the thoracic and lumbar spine. Eur Spine J 2001;10(5): 396 - 402. [14] Landreneau R, Hazelrigg S, Mack M. Postoperative pain-related morbidity. Video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56:1284 - 9. [15] Matthews HH, Evans MT, Molligan HJ, et al. Laparoscopic discectomy with anterior interbody fusion: a preliminary review. Spine 1995;20:1797 - 802. [16] Mayer H. A new microsurgical technique for minimal invasive anterior lumbar interbody fusion. Spine 1997;22:691 - 700. [17] Maynard Jr FM, Bracken MB, Creasey G, et al. International standards for neurological and functional classification of spinal cord injury. Spinal Cord 1997;35:266 - 74. [18] McAfee P, Regan J, Zdeblick T, et al. The incidence of complications in endoscopic anterior thoracolumbar spinal reconstructive surgery. A prospective multicenter study comprising the first 100 consecutive cases. Spine 1995;20(14):1624 - 32. [19] Muhlbauer M, Pfisterer W, Eyb R, et al. Minimally invasive retroperitoneal approach for lumbar corpectomy and anterior reconstruction. Technical noteJ Neurosurg 2000;93(1 Suppl):161 - 7. [20] Olsen D, McCord D, Law M. Laparoscopic discectomy with anterior interbody fusion of L5-S1. Surg Endosc 1996;10:1158 - 63. [21] Oskouian R, Shaffrey C, Whitehill R, et al. Anterior stabilization of three-column thoracolumbar spinal trauma. J Neurosurg Spine 2006;5(1):18 - 25. [22] Pappou I, Papadopoulos E, Swanson A, et al. Pott disease in the thoracolumbar spine with marked kyphosis and progressive paraplegia necessitating posterior vertebral column resection and anterior reconstruction with a cage. Spine 2006;31(4):E123 - 7. [23] Payer M. Immediate open anterior reduction and antero-posterior fixation/fusion for bilateral cervical locked facets. Acta Neurochir (Wien) 2005;147(5):509 - 13. [24] Pflugmacher R, Schleicher P, Schaefer J, et al. Biomechanical comparison of expandable cages for vertebral body replacement in the thoracolumbar spine. Spine 2004;29(13):1413 - 9. [25] Regan JJ, Guyer RD. Endoscopic techniques in spinal surgery. Clin Orthop 1997;335:122 - 39. [26] Sasso R, Renkens K, Hanson D, et al. Unstable thoracolumbar burst fractures: anterior-only versus short-segment posterior fixation. J Spinal Disord Tech 2006;19(4):242 - 8. [27] Visocchi M, Masferrer R, Sonntag V, et al. Thoracoscopic approaches to the thoracic spine. Acta Neurochir 1998;140(8):737 - 43.
Commentary This is a well-written article emphasizing the advantages of the mini-open anterior approach to the thoracolumbar spine in cases of unstable vertebral body fracture or vertebral body tumour. The SynFrame retractor allows sufficiently good override control of the operative field. Endoscopic procedures allow shorter stay in hospital with an ensuing lower cost. However, the mini-open procedure is probably safer: reconstruction procedure (cage instrumentation and plating) and treatment of possible complication are easier than by the endoscopic technique, which, in the case of intraoperative complication, sometimes requires an immediate subsequent open procedure. In all the traumatic lesions of this series, a combined 2stage procedure has been used: posterior transpedicular