Lateral Lumbar Interbody Fusion in the Prone Position

Lateral lumbar interbody fusion (LLIF) is a well-established technique for the surgical treatment of lumbar spine disorders. Lateral interbody approaches have many advantages, as they tend to be muscle-sparing, have high fusion rates, and can correct deformity in both the coronal and sagittal planes. One historical disadvantage of LLIF has been the prolonged operative time required to reposition patients to perform posterior decompression and/or instrumentation.

Single-position lateral lumbar interbody fusion (SP-LLIF), in which both portions of the procedure are performed without repositioning the patient, was developed in order to overcome this disadvantage. Early research has shown the technique to be effective, with multiple studies demonstrating reduction in operative time and length of stay with equivalent clinical outcomes compared to “two-position” LLIF.[1,2] Traditional SP-LLIF has historically been performed with the patient in lateral decubitus. This requires posterior instrumentation and/ or decompression to be performed in a relatively unfamiliar position for the spine surgeon. Despite favorable outcome data, this technical disadvantage has limited the adoption of the procedure.

Prone lateral lumbar interbody fusion (P-LLIF) was developed to overcome this disadvantage and allows the surgeon to perform posterior approaches to the spine in a familiar position, while simultaneously allowing access to the anterior column via a retroperitoneal approach. The technique was first reported in the literature in February 2020 by Lamartina and Berjano.[3] In recent years, substantial interest has grown in performing lateral interbody approaches in the prone position. Surgery in the prone position comes with several advantages related to feasibility of performing decompression, revising posterior instrumentation for extension of fusion/pseudoarthrosis, performing posteriorly based osteotomies, and the ability for co-surgeons to perform simultaneous retroperitoneal and posterior surgery. Potential disadvantages associated with the prone position include difficulty in managing complications, technical/ ergonomic challenges in retroperitoneal retractor placement, and the potential for retractor migration during the procedure. Several published case series describe early clinical outcomes with P-LLIF. Lamartina and Berjano’s original article describing the technique contained 7 patients.[3] They reported a mean reduction in Oswestry Dis- ability Index (ODI) from 48.5 ± 21.0 to 14.6 ± 18.5 at an average postoperative follow-up of 6 months. Back and leg pain visual analog scale (VAS) scores were reduced from 7.7 ± 1.7 to 1.7 ± 2.9 and 8.5 ± 1.2 to 2.7 ± 3.3, respectively. In an 11-patient series, Godzik et al reported similar reductions in ODI (55.1 ± 30.4 to 28.5 ± 18.0) and back pain VAS (6.0 ± 2.3 to 1.6 ± 0.8).[4] These data were collected relatively early in the postoperative period at an average follow-up of 2 months. The most recent clinical series of patients undergoing P-LLIF was published by Farber et al and included 28 patients with an average follow-up of 3 months.[5] In this series, ODI was reduced from 25.4 ± 9.0 to 12.3 ± 6.9. VAS back (7.0 ± 2.9 to 3.3 ± 1.6) and VAS leg (6.2 ± 3.5 to 3.3 ± 3.0) scores also improved, albeit to a lesser extent than in other early case series.

Radiographic outcomes related to segmental and overall lumbar lordosis restoration appear favorable in P-LLIF. Pimenta et al reported on a series of 32 patients undergoing single and multilevel procedures. These authors reported an average increase in segmental lordosis from 8.7° to 14.8° postoperatively (P < 0.001).6 A large retrospective multicenter series that included 364 patients reported an average increase in overall lumbar lordosis of 4.8° (preoperative: 45.6°; postoperative: 50°; P < 0.001).

P-LLIF was developed to overcome the technical disadvantage of SPLLIF, which is traditionally performed in the lateral decubitus position. P-LLIF allows the surgeon to perform posterior approaches to the spine in a familiar position while simultaneously allowing access to the anterior column via a retroperitoneal approach.

Two recent retrospective analyses have compared radiographic alignments following P-LLIF with that of traditional two-position LLIF.[7,8] Walker et al found a greater improvement in segmental (5.1° vs 2.5°; P = 0.02) but not overall lumbar lordosis (6.3° vs 3.1°; P = 0.14) after P-LLIF when compared with two-position LLIF.[7] In contrast, Soliman et al’s recent retrospective series found P-LLIF to have significantly greater improvement in overall lumbar lordosis when compared with two-position LLIF (9.9° vs 0.5°; P = 0.047).[8] Changes in segmental lordosis were not reported in this study.

The complication profile of P-LLIF appears similar to traditional LLIF and includes sensorimotor deficits, psoas hematoma, anterior longitudinal ligament (ALL) rupture, and visceral or vascular injury. In Lamartina and Berjano’s original series of 7 patients, they reported 1 ALL rupture and 1 patient with persistent sensory loss in the thigh more than 3 months after surgery.[3] In Godzik et al’s 11-patient series, 1 patient had urinary retention and 2 patients had postoperative thigh pain that resolved by postoperative day 7.[4] Pimenta et al reported 1 psoas hematoma and 4 transient unspecified neurological deficits in their initial series of 32 patients.[6] In the 28-patient series by Farber et al, 2 ALL ruptures were reported.[5] Two patients had sensory deficits that persisted beyond 6 weeks. The authors reported 1 patient with an infection and 1 patient who required early return to surgery for direct decompression at postoperative day 8. No reports of great vessel or visceral injury exist in the early P-LLIF literature.

P-LLIF is a potentially powerful technique for minimally invasive lumbar fusion that offers advantages related to the familiarity of the prone position and straightforward access to the posterior spine. Early data suggest that the technique is clinically effective, capable of significant restoration of lumbar lordosis, and has a similar complication profile to that of traditional LLIF. Surgeons interested in adopting the technique should be aware that the literature to date includes only retrospective studies and that many authors reported conflicts of interest related to industry. Further prospective studies of P-LLIF are needed to evaluate long-term clinical and radiographic outcomes in comparison to well-established traditional techniques.

1. Buckland AJ, Braly BA, O’Malley NA, et al. Lateral decubitus single position anterior posterior surgery improves operative efficiency, improves perioperative putcomes, and maintains radiological outcomes comparable with tradition anterior posterior fusion at minimum 2-year follow-up [advance online publication January 11, 2023]. Spine J. https:// doi.org/10.1016/j.spinee.2023.01.001

2. Keorochana G, Muljadi JA, Kongtharvonskul J. Perioperative and radiographic outcomes between single-position surgery (lateral decubitus) and dual-position surgery for lateral lumbar interbody fusion and percutaneous pedicle screw fixation: meta-analysis. World Neurosurg. 2022;165:e282–e291.

3. Lamartina C, Berjano P. Prone single-position extreme lateral interbody fusion (Pro-XLIF): preliminary results. Eur Spine J. 2020;6–13.

4. Godzik J, Ohiorhenuan IE, Xu DS, et al. Single-position prone lateral approach: cadaveric feasibility study and early clinical experience. Neurosurg Focus . 2020;49:E15.

5. Farber SH, Naeem K, Bhargava M, et al. Single-position prone lateral transpsoas approach: early experience and outcomes. J Neurosurg Spine. 2022;36:358–365.

6. Pimenta L, Amaral R, Taylor W, et al. The prone transpsoas technique: preliminary radiographic results of a multicenter experience. Eur Spine J. 2021;30:108–113.

7. Walker CT, Farber SH, Gandhi S, et al. Single-position prone lateral interbody fusion improves segmental lordosis in lumbar spondylolisthesis. World Neurosurg. 2021;151:e786–e792.

8. Soliman MAR, Khan A, Pollina J. Comparison of prone transpsoas and standard lateral lumbar interbody fusion surgery for degenerative lumbar spine disease: a retrospective radiographic propensity score-matched analysis. World Neurosurg. 2022;157:e11–e21.