- Cross-sectional imaging demonstrating nerve root compression and concordant symptoms.
- Leg pain for at least 6 weeks.
- Insufficient pain relief with conservative management.
- Oral steroids.
- Non-steroidal anti-inflammatory drugs.
- Physical therapy.
- Epidural injections.
- Progressive motor symptoms.
- Any signs of cauda equine syndrome.
- Saddle anesthesia, urinary retention/bladder overflow incontinence or the inability to control bowel movements.
A thorough history and physical examinations must be considered along with imaging studies to determine if the patient’s principal source of symptoms stem from the spondylolisthesis, recurrent disk herniation or degenerative disk disease.1 Appropriate nonsurgical management including anti-inflammatory medications, physical therapy and possibly epidural steroid injections should be attempted first, and surgical options are reserved for situations in which nonsurgical care fails to significantly reduce symptomatology. However, early surgical intervention is indicated for signs of cauda equina syndrome, deteriorating neurological deficits, or debilitating pain.2
Surgery may be relatively contraindicated when other conditions coexist that can mimic the symptoms. Any alternate pathology, such as those listed below, must be taken into consideration when determining whether surgery is appropriate.
- Compression of the peroneal nerve at the fibular head.
- Irritation of the sciatic nerve by the piriformis muscle.
- Vitamin B deficiency.
- Systemic diseases.
- Multiple sclerosis.
In addition, patients with a body mass index >40 can make the working distance longer and the procedure technically more difficult. Performing >2 levels can also be challenging using minimally invasive techniques. Finally, in patients with osteoporosis an uninstrumented fusion may be considered to avoid potential complications of hardware failure.
Instruments and Materials Required
- Open Jackson table with platform.
- Intraoperative radiography or fluoroscopy.
- Surgical loupes or microscope.
- Microsurgical instrument set.
- High speed burr.
- Cannulated pedicle screws with guide wires, jamshidi needles and rod passer.
The patient is placed prone on the OR table. The authors’ prefer to use an open Jackson frame with the platform for extension of hips and pillows for flexed knees. This allows restoration of lumbar lordosis. Hip pads are placed around the anterior superior iliac spines and all bony prominences are well padded. Arms are placed on arm boards with elbows flexed to ~90 degrees and the shoulders abducted and externally rotated. The patient is then prepped and draped in usual sterile fashion.
Once the patient has been positioned, anterior-posterior fluoroscopy is used to mark the respective pedicles, vertically along the lateral border of the pedicle and horizontal along the midpoint of the pedicle.
Step 1: Incision and Exposure
The side of the most significant leg pain is generally chosen for a transforaminal lumbar interbody fusion (TLIF) exposure. A local nerve block may be performed by infiltrating the paraspinal muscles with an anesthetic (eg, bupivacaine hydrochloride and epinephrine). Bilateral vertical skin incisions are made 4 cm off midline, inline with the lateral border of the pedicle with a #15 scalpel blade. This is continued down to the lumbodorsal fascia. The fascia is then sharply incised vertically inline with the incision. Blunt dissection is performed with the surgeon’s finger between the lumbar paraspinal muscle bellies down to the facet joint (Supplemental Video, Supplemental Digital Content 1, http://links.lww.com/CLINSPINE/A118).
Step 2: Guidewire placement
Using anterior-posterior and lateral radiographs, the jamshidi needle is placed at down through the incision to the lateral midpoint of the pedicle. Positioning is confirmed on fluoroscopy. The jamshidi is impacted into the pedicle 20 mm. Fluoroscopy is used to ensure the jamshidi does not violoate the medial wall of the pedicle. A guidewire is placed through the jamshidi needle and inserted an additional 10 to 20 mm. The jamshidi is then removed leaving the guidewire in place. This process is then repeated for each pedicle.
Step 3: Docking
The fluoroscopy is then changed to the lateral projection. The starting dilator is placed on the caudal aspect of the cephalad vertebrae (ie, L4 lamina in and L4–L5 TLIF). Sequential dilators are placed up to a 22-28 mm tubular retractor. In some cases the authors have found that using a sweeping motion medial-lateral and cephalad-caudal can assist with bony exposure. Anterior-posterior fluoroscopy is obtained to confirm appropriate placement of the tubular retractor. The tubular retractor is secured to the Jackson frame.
Step 4: Approaching the Discectomy Window
Electrocautery is used to remove the facet capsule and identify the ipsilateral cephalad lamina and ipsilateral caudal lamina. An AM8 side cutting bur is used to resect the inferior articular facet of the cephalad level at the level of the pars in line with the inferior endplace of the cephalad lamina. The burr is also used to remove the inferior half of the cephalad lamina. A kerrison rongeur is used to resect the superior articular facet and skeletonize the caudal pedicle. The ligamentum flavum is resected from the cephalad and caudal lamina to reveal the traversing nerve root and intervertebral disk. A penfield #4 is used to sweep the traversing nerve room medially and gently retracted with a D’Errico or Love nerve root retractor. The disk is then exposed. Epidural veins are ligated using a bipolar electrocautery.
Step 5: Discectomy
A #15 scalpel blade is used to incise the disk annulus, creating a rectangular window. A thorough discectomy is then performed using shavers and curettes. A pituitary is used to remove the disk fragments. Currettes are used to remove the cartilaginous endplates to provide fully denuded surfaces. The disk space is then irrigated.
Step 6: Interbody Device
Trial sizer spreaders are used to ascertain a snug fit. The autograft is morselized and packed within the interbody cage and into the disk space, anterior to the cage. The cage is then impacted. The remainder of the disk space is packed with morselized allograft. Surgeons often also augement the bone graft with a biological to enhance bony fusion.
Step 7: Pedicle Screw Placement
A tap is then placed over the guidewire followed by placement of the pedicle screw. The same steps are performed for each pedicle. In some cases screws are then tested using EMG neuromonitoring. In some cases a rod is then passed through the tulip heads. Set screws are applied and torqued.
Step 8: Closure
The wound is then copiously irrigated. All bleeding should be controlled using hemostatic agents and electrocautery. The wound is closed in multiple layers, and a sterile dressing is placed.
- Dural tear (cerebrospinal fluid leak).
- Does not change the results of surgery, however depending on the size of the tear and the adequacy of the repair, this may change the postoperative management.3
- Nerve root damage.
- Permanent weakness.
- Chronic dysesthesias.
- Hardware malposition.
- Persistent and progressive symptoms.
- Medical complications.
PEARLS AND PITFALLS
Care should be taken to protect the traversing and exiting nerve root, particularly with passage of devices into and out of the disk space, including the interbody cage. One must ensure enough of the facet joint complex is resected for adequate visualization.
Perfect anteroposterior and lateral fluoroscopic images are critical to accurate placement of the instrumentation. Experienced radiology technicians can be very helpful with this.
Always use the pedicle as the landmark.
The dura may be thin or adhesed to the ligamentum flavum in severe central stenosis or in the area of a previous epidural steroid injection, predisposing to a tear. Care must also be taken when releasing the upper insertion of the ligamentum, as the dura can often become adherent to the undersurface of the lamina, or where the ligamentum flavum becomes confluent with the facet capsule. It is helpful to have a “dural repair” tray available, including Castroviejo needle drivers and long, thin bayonet forceps, which are easier to manipulate in a small microsurgical incision.
Patients are typically discharged postoperative day 1 or 2. The authors recommend no heaving lifting, twisting, or bending for 12 weeks.
1. Selznick LA, Shamji MF, Isaacs RE. Minimally invasive interbody fusion for revision lumbar surgery: technical feasibility and safety. J Spinal Disord Tech. 2009;22:207–213.
2. Peng CW, Yue WM, Poh SY, et al. Clinical and radiological outcomes of minimally invasive versus open transforaminal lumbar interbody fusion. Spine (Phila Pa 1976). 2009;34:1385–1389.
3. Sclafani JA, Kim CW. Complications associated with the initial learning curve of minimally invasive spine surgery
. Clin Orthop Relat Res. 2014;472:1711–1717.