LLIF T12/L1-L2

37 LLIF T12/L1-L2

Cristiano Magalhães Menezes and Érica Godinho Menezes

Summary

The lateral transpsoas approach to the T12/L1-L2 (thoracolumbar junction) level requires careful management of the diaphragm, the pleura and the 11th and 12th ribs. In this chapter, the authors describe these steps with a couple of cases and a very comprehensive video, sharing their experience and the complication avoidance tips and tricks.

Keywords: XLIF MIS thoracolumbar corpectomy thoracic disc herniation

37.1 Introduction

The lateral lumbar interbody fusion (LLIF) procedure described by Ozgur et al 1 to address different conditions in lumbar spine, has become increasingly popular to achieve fusion due to the advantages of smaller incisions, decreased blood loss, and shorter hospital stays.²^,³^,⁴^,⁵ The development of the technique permitted not only interbody fusion but also indirect decompression neural elements, corpectomies, restoration of vertebral height, alignment, and stabilization, especially in thoracic and thoracolumbar segments, where lumbar plexus is not a concern.³^,⁴^,⁵

There are multiple indications for LLIF in thoracolumbar region including traumatic and degenerative conditions.²^,³^,⁴ It is part of any multilevel surgery, starting at lower lumbar levels, as in scoliosis surgery, or targeting the thoracolumbar junction, as in a corpectomy to treat a fracture.

The thoracolumbar junction (T11L1) challenges the spine surgeon’s anatomy knowledge, especially the diaphragm anatomy, which separates the thoracic and abdominal cavities.²^,⁶^,⁷^,⁸ Dealing with this complex anatomic region, using a minimally disruptive anterolateral corridor for T12L1 cases, is the key to decreasing morbidity of open thoracophrenolumbotomies. For this, it is crucial to keep dissection out of the pleural cavity, using an extracavitary approach, mastering the specific anatomy of the region to mobilize the thoracic diaphragm in a reproducible and safe manner.² A retropleural approach is used when a plane between the parietal pleura and inner surface of the rib inferior to the access incision is created with the diaphragm and pleura retracted and dissected anteriorly.⁶ This enables the approach to the spine, vertebral body, and disc spaces as well as ventral dural sac for decompression from a lateral trajectory.

In this chapter, we describe the technique for minimally invasive lateral retropleural approach at T12/L1 using the LLIF tubular expandable retractor, the potential pitfalls, and expected outcomes.

37.2 Indications

There are many potential indications for a retropleural LLIF approach at the thoracolumbar junction, including degenerative, deformity, trauma, tumor, and infection of the spine.

Over the past decade, less invasive surgical approaches for neural decompression and fusion have been popularized and recently applied for the treatment of degenerative conditions. Single degenerative disc disease at T12L1 and thoracolumbar disc herniation with conus medullaris compression are examples of these indications (Fig. 37.1). More commonly, T12L1 multiple-level LLIF surgery for adult spinal deformity is an attempt to achieve sagittal and coronal alignment with decreased morbidity. The lateral approach may be used as part of a minimally invasive anterior-only or anterior-posterior procedure for the management of degenerative scoliosis, or may be combining it with an open posterior fusion with or without osteotomies.³^,⁹^,¹⁰

Fig. 37.1 Single-level degenerative disc disease at T12L1 with Modic 1 changes.

In traumatic fractures, this approach can be used in association with percutaneous short segment posterior fixation or with modern lateral or anterior plates to perform a thoracolumbar corpectomy.¹¹ The same can be done for corpectomies due to spinal tumors (Fig. 37.2), aiming at palliation, stabilization, spinal cord decompression, pain control, and overall quality of life improvement.¹² It is also possible that through lateral access surgery, the spinal canal can be reached for certain tumor resections. An example of an infectious case that can be approached laterally is a thoracolumbar discitis case where this can be safely approached through a mini-open lateral approach.

Fig. 37.2 Pathologic fracture due a plasmacytoma at T12. (a) Anteroposterior X-ray; (b) sagittal magnetic resonance imaging (MRI), T2-weighted image; (c) intraoperative fluoroscopic image; (d) expandable cage positioned after corpectomy.

37.3 Contraindications

Relative contraindications include: anomalous vascular anatomy, such as lateralized vessels (deformity cases with vertebral rotation) or the presence of the artery of Adamkiewicz on the surgical corridor; vascular disease; retroperitoneal or retropleural scar due to prior surgery; intense pleural inflammatory reaction due to infection (spondylodiscitis); when posterior direct decompression is required; when potential bony structures could limit the access (large osteophytes); morbid obesity; and thoracic or pulmonary anomalies.

Thus, it is mandatory to evaluate the spine orientation and rotation effects on vascular and visceral structures in order to determine if a safe working channel can be achieved.

37.4 Preoperative Planning

It is important to identify patients suitable for a lateral LLIF approach to the thoracolumbar junction based on the patient’s pathology and anatomy, as well as on surgeon’s proficiency. Patient selection, with special attention to patient’s medical history and those potential contraindications to the anterior approach to spine, as well as correct evaluation of anteroposterior (AP) and lateral X-ray and axial magnetic resonance imaging (MRI), is critical.

The operating room (OR) setup for a lateral procedure must be planned to optimize the efficiency and workflow. The surgical bed is oriented in order to fit the patient properly and still have enough room to place the fluoroscopy monitor and neuromonitoring machine directed toward the surgeon and the OR personnel. Ensuring a clear path for C-arm travel into the room and to the ventral side of the patient is recommended. A mayo stand is placed toward the feet of the bed, allowing access to the scrub nurse, and avoiding interfering with the C-arm or surgeon. If the bed needs to be reversed, move the headpiece to the caudal part of the bed and reposition the arm board in line with the axilla on the ventral side of the patient (Fig. 37.3).

Fig. 37.3 In the operating room, the setup for lateral procedure must be planned to optimize the efficiency and workflow. The surgical bed is oriented in order to fit the patient properly.

Dual lumen intubation can be used to reduce lung size on the operative side, but it is not routinely necessary. It can be achieved by reducing the insufflation tidal volume and increasing the respiration rate to keep the patient oxygenated during anesthesia.

37.5 Patient Positioning

After intubation and general anesthesia, with the back facing the surgeon and in lateral decubitus, the patient is placed approximately 4 to 6 inches from the posterior edge of the bed. The head of the patient needs to be supported and should face the anesthesiologist to ensure adequate access to the face and the endotracheal tube. Place an axillary roll under the patient’s downside axilla while maintaining space for the C-arm to enter the sterile field. Padding to protect the patient’s nipple, peroneal nerve, and lateral malleolus of the ankle is also recommended.

Now, the torso of the patient is adjusted approximating the spine until a true AP fluoroscopy is achieved. The surgeon needs to instruct the C-arm technician to take AP shots, adjusting the patient until true images can be achieved (both the pedicles and a single linear end plate can be seen above and below the vertebrae at the area of interest). Once this has been achieved, hold the patient in this position while ensuring the C-arm is clear of chest taping site. At the level of patient’s chest, tape from the anterior side of the bed, taping around the chest, over padded nipple, adhering tape directly to the patient’s skin on the lateral aspect of the chest, while holding the patient in true AP of the operative level. Adhere the tape to the posterior rail of bed, continuing under to meet the tape at its origin. Without tearing the tape, repeat one more loop. Secure the patient’s arms to an arm board. Use pads between under the lateral downside to protect the shoulders (Fig. 37.3). With the aid of an assistant, adhere tape in front of the bed, below the break on anterior side of the patient. Pull the tape up and over the crest, adhering it directly to the skin just below the iliac crest. Without tearing the tape, continue under the bed to go around the patient and repeat until completing one more loop around the patient. Adhere a new piece of tape just below the iliac crest, pulling across the lateral thigh, over the padded knee, and under the anterior side of the bed, emerging at the patient’s foot. Continue pulling tape over the padded ankle, cross over the padded knee, then under the anterior section of bed, emerging posteriorly at level of the patient’s hip (before the break), and continue the tape until it overlaps the initial starting point of this piece of tape. Retractor attachment (flexible arm) should be placed at the posterior side of the patient in line with his/her scapula (Fig. 37.4a).