C-arm-free oblique lumbar interbody fusion at the L5-S1 level (OLIF51) and simultaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This technique does not expose the surgeon or operating staff to radiation hazards.
Oblique lumbar interbody fusion (OLIF) is an established technique for the indirect decompression of lumbar canal stenosis. However, OLIF at the L5-S1 level (OLIF51) is technically difficult because of the anatomical structures. We present a novel simultaneous technique of OLIF51 with percutaneous pedicle screw fixation without fluoroscopy. The patient is placed in a right lateral decubitus position. A percutaneous reference pin is inserted into the right sacroiliac joint. An O-arm scan is performed, and 3D reconstructed images are transmitted to the spinal navigation system. A 4 cm oblique skin incision is made under navigation guidance along the pelvis. The internal/external and transverse abdominal muscles are divided along the muscle fibers, protecting the iliohypogastric and ilioinguinal nerves. Using a retroperitoneal approach, the left common iliac vessels are identified. Special muscle retractors with illumination are used to expose the L5-S1 intervertebral disc. After disc preparation with navigated instruments, the disc space is distracted with navigated trials. Autogenous bone and demineralized bone material are then inserted into the cage hole. The OLIF51 cage is inserted into the disc space with the help of a mallet. Simultaneously, percutaneous pedicle screws are inserted by another surgeon without changing the lateral decubitus position of the patient.
In conclusion, C-arm-free OLIF51 and simultaneous percutaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This novel technique reduces surgical time and radiation hazards.
Spondylosis is regarded as a stress fracture1 and occurs in about 5% of the young adult population2. The most common level of occurrence is at the L5 level due to the unique shearing force applied at the L5-S1 area. The main symptoms of spondylosis and spondylolisthesis are low back pain, leg pain, and numbness. If conservative treatment proves ineffective, surgical treatment is recommended3. Transforaminal lumbar interbody fusion (TLIF) is an effective and established technique4, but the nonunion rate of this procedure is relatively higher at the L5-S1 level5. Furthermore, with TLIF, it is difficult to create adequate lordosis compared to oblique lumbar interbody fusion (OLIF) or anterior lumbar interbody fusion (ALIF)6.
Indirect decompressions such as ALIF or OLIF are currently common methods for treating lumbar stenosis7. However, the conventional ALIF technique causes a large amount of muscle damage. Oblique lateral interbody fusion at the L5-S1 level (OLIF51) was first reported in 20178. Posterior instrument augmentation is usually necessary to ensure solid fusion, but the conventional OLIF technique uses a C-arm, and the patient position is changed from lateral to prone. To overcome these problems, we report herein a novel technique of C-arm-free simultaneous OLIF51 and percutaneous pedicle screws (PPSs) in a single lateral position.
We introduce the case of a 75-year-old woman with symptomatic L5 spondylolisthesis (grade 2).
This study was approved by the ethics committee at Okayama Rosai Hospital (No. 201-3).
1. Patient examination
2. Evaluation of images
Figure 1: Preoperative image. (A) Midsagittal reconstruction CT, (B) T2 weighted midsagittal image, (C) CT MRI fusion image. CT and MRI show grade 2 isthmic spondylolisthesis. The vascular window is 37 mm. Please click here to view a larger version of this figure.
3. Patient positioning and neuromonitoring
Figure 2: Patient positioning. Right lateral decubitus position secured with tape. Please click here to view a larger version of this figure.
Figure 3: Neuromonitoring. Neuromonitoring is preferable for this technique. Please click here to view a larger version of this figure.
4. Intraoperative CT and spinal navigation
Figure 4: O-arm. One O-arm scan is just 23 s. Please click here to view a larger version of this figure.
Figure 5: Navigation system. Every instrument is navigated with this system. Please click here to view a larger version of this figure.
5. Navigated instrument registration
6. Incision and muscle dissection
Figure 6: Skin incision. The skin is marked using a navigated pointer, which is directed to the center and parallel to the L5-S1 Please click here to view a larger version of this figure.
Figure 7: Navigated pointer. The white arrow indicates a navigated pointer. Please click here to view a larger version of this figure.
7. Disc preparation and trialing
Figure 8: Approach to the promontorium. (A) Navigated pedicle probe, (B) navigation monitor. A navigated pedicle probe (white arrow) is used to check the L5-S1 disc level. Please click here to view a larger version of this figure.
Figure 9: Self-retaining retractors. These three retractors retract both common iliac vessels and the bifurcation. Please click here to view a larger version of this figure.
Figure 10: Navigated shaving. (A) Navigated shaver, (B) navigation monitor. Navigated shavers are from 6 mm to 12 mm. Please click here to view a larger version of this figure.
Figure 11: Navigated curved curette. (A) Navigated curved curette, (B) navigation monitor. A navigated curved curette is very useful to completely remove the posterior part of the disc. Please click here to view a larger version of this figure.
Figure 12: Trialing. After disc preparation, the disc space is sequentially distracted with navigated trials (white arrow). Please click here to view a larger version of this figure.
8. Cage placement and screwing
Figure 13: Cage placement and screwing. (A) OLIF51 cage at the L5-S1 disc, (B) cage with screw. A mixture of autogenous bone and demineralized bone material is inserted into the cage hole. Please click here to view a larger version of this figure.
9. Simultaneous percutaneous pedicle screw (PPS) fixation
Figure 14: Simultaneous PPS fixation. PPSs are inserted in the same single lateral position by another surgeon under navigation guidance. Please click here to view a larger version of this figure.
10. Postoperative procedure
Fourteen cases (average age: 71.5 years) were treated using this new technique. They were compared to 40 cases (average age: 74.0 years) of L5-S1 TLIF. L5-S1 lordosis angle and disc height were measured in both groups. The OLIF51 group obtained a better L5-S1 lordosis than the TLIF 51 group (Figure 15).
Figure 15: Radiological measurement. (A) Antero-inferior corner, (B): postero-inferior of the upper vertebra, (C) antero-superior corner, (D) postero-superior corner of the lower vertebra. Disc height = EF, segmental lordosis = angle AGC. Please click here to view a larger version of this figure.
Preoperative L5/S1 angle | Postoperative L5/S1 angle | Preoperative L5/S1 disc height | Postoperative L5/S1 disc height | |
OLIF 51 (N=14) | 11.4+-4.1° | 21.3+-3.3° | 7.2 +-2.1mm | 10.9+-1.8 mm |
TLIF 51 (N=40) | 10.1+-4.4° | 12.1+-4.7° | 8.6+-2.7 mm | 9.4+-1.8 mm |
not significant | p<0.05 | not significant | p<0.05 |
Table 1: L5-S1 disc angle and height for OLIF51 versus TLIF51.
Recently, the lateral lumbar approach for interbody fusion has been gaining popularity due to its minimal invasiveness9. Among these approaches, the direct lateral psoas splitting approach has several disadvantages, such as lumbar nerve plexus injury and psoas muscle weakness10. To reduce these complications, prepsoas or OLIF was introduced by Davis et al. in 201411. However, it is difficult to operate at the L5-S1 disc due to its anatomical features. In 2017, a novel technique was devised to approach the L5-S1 disc in a lateral position (OLIF51), enabling interbody fusion from the lower thoracic spine to L5-S1 8. The advantages of OLIF51 are good anterior release, a greater bone graft, greater stability that is suitable for osteoporosis, and a high fusion rate12. The applicability of OILF51, however, is restricted due to the location of the blood vessels, which may restrict the access.
Strict criteria for patient selection and careful preoperative planning are necessary for this technique. This procedure is carried out with the patient in a lateral decubitus position, offering the advantage of inserting the PPSs in the same position, thus reducing both operating time and blood loss13. The conventional OLIF51 technique with PPS insertion entails radiation exposure. Occupational radiation exposure is one of the main issues of concern for minimally invasive spinal surgeons14. Repeated multiplanar images are necessary for accurate screw and cage insertion, increasing both radiation exposure and operating time. With O-arm guided navigation, the radiation exposure to the patient is reduced due to the use of low-resolution mode and the small FOV of the O-arm. The time required for an O-arm scan is less than 24 s, which is an equivalent dose to that of 90 s of fluoroscopy. This has been shown to eliminate the need for cumbersome lead protective gear, clear the surgical field of the C-arm, and reduce radiation exposure without compromising the accuracy15.
Another advantage of this technique is achieving OLIF from L1 to L5. Especially for adult spinal deformity, this technique is very useful because five level OLIF cages from the L1 to S1 level in a single lateral position can be inserted. Compared with the conventional technique, changing the patient position is not required for this technique, decreasing the surgical time and the total cost of the surgery. For future applications, robotic surgery can be combined with this novel technique.
The critical steps of our new technique are as follows. First, a preoperative evaluation of the location of common iliac vessels is done, and a vascular window less than 20 mm is a contraindication for OLIF51. CT-MRI fusion image is recommended for this purpose16. Second, the reference frame pin is firmly inserted into the left sacroiliac joint percutaneously17. If the reference frame is moved, the accuracy of this procedure decreases, risking screw or cage malpositioning. If any doubt exists regarding the navigation accuracy, an O-arm scan should be performed. Third, navigated instruments including a pointer, pedicle probe, shaver, Cobb elevator, curette, and trial should be used effectively. In particular, navigated curved curettes are useful for this C-arm-free procedure18. As an alternative, a C-arm technique is also available for this simultaneous method.
Certain limitations to this technique must be considered. Relatively expensive equipment (the O-arm and navigation system) is necessary, and there is a steep learning curve for this technique. A vascular window less than 20 mm poses a contraindication for this procedure. Further studies in the form of case series are required to further corroborate the effectiveness of this technique in managing isthmic spondylolisthesis.
C-arm-free OLIF51 and simultaneous percutaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This novel technique reduces surgical time and radiation hazards to surgeons and operating staff.
The authors have nothing to disclose.
This study was supported by the Okayama Spine Group.
Adjustable hinged operating carbon table | Mizuho OSI | 6988A-PV-ACP | OSI Axis Jackson table |
CD Horizon Solera Voyager | Medtronic | 6.4317E+11 | Percutaneous pedicle screw system |
Navigated Cobb elevator | Medtronic | NAV2066 | |
Navigated combo tool | Medtronic | NAV2068 | |
Navigated curette | Medtronic | NAV2069 | |
Navigated high speed bur | Medtronic | EM200N | Stelth |
Navigated passive pointer | Medtronic | 960-559 | |
Navigated pedicle probe | Medtronic | 9734680 | |
Navigated shaver | Medtronic | NAV2071 | |
NIM Eclipse system | Medtronic | ECLC | Neuromonitouring |
O-arm | Medtronic | 224ABBZX00042000 | Intraoperative CT |
Radiolucent open spine cramp | Medtronic | 9731780 | |
Self-retaining retractor | Medtronic | 29B2X10008MDT151 | |
Sovereign Spinal System | Medtronic | 6.4317E+11 | OLIF51 cage |
Spine small passive frame | Medtronic | 9730605 | |
Stealth station navigation system Spine 7R | Medtronic | 9733990 | Navigation |
U-NavLock Gray | Medtronic | 9734590 | |
U-NavLock Green | Medtronic | 9734734 | |
U-NavLock Orange | Medtronic | 9734683 | |
U-NavLock Violet | Medtronic | 9734682 |