Patients were age 54.1 ± 10.6 years (range, 14.9 to 77.4 years). There were 148 females age 54.5 ± 11.0 years (range, 14.9 to 77.4 years) and 31 males age 52.2 ± 8.7 years (range, 27.2 to 67.7 years). There were 118 primary cases and 61 revision cases. There was no occurrence of revision after a previous anterior approach. Diagnosis at the time of surgery is shown in . Weight and BMI were respectively 67.1 ± 14.5 kg (range, 35 to 116 kg) and 24.8 ± 4.1 kg/m2 (range, 15.6 to 38.6 kg/m2). Follow-up was 0.94 ± 0.72 years on average and 17 patients had more than two years of follow-up.
Four patients with scoliosis and one patient with L4-5 degenerative spondylolisthesis had a right-sided approach. Details of the levels approached with the respective operative blood loss, operation time and length of hospital stay are provided in . The procedure was performed at discs L1-2 in 4, L2-3 in 54, L3-4 in 120, L4-5 in 134, and L5-S1 in 6 patients. It was done at a single level for 56, two levels for 107, and three levels for 16 patients. shows radiographs of a patient with a three-level OLIF at L2-5, while shows two different patients with L1-3 and L4-S1 OLIF, demonstrating the potential use of the described technique for approaching L1-2 and L5-S1 levels, respectively.
Levels approached with respective operative blood loss, operative time and length of hospital stay
Fig. 3 Preoperative (A, B) and postoperative (C, D) radiographs of a 45-year-old female with degenerative
scoliosis undergoing three-level oblique lumbar interbody fusion, showing the presence radio-opaque markers
of the interbody cages from L2 to L5 (arrows). (more ...)
Postoperative radiographs of two different patients undergoing oblique lumbar interbody fusion at L1-3 (A, B) and L4-S1 (C, D). Full arrows show the presence radio-opaque markers of the interbody cages.
In three patients, the procedure was aborted for one level. For the first patient, an L3-5 OLIF was planned but only L4-L5 was performed. Surgery at the L3-4 level was not performed because the disc space was too narrow for the smallest cage. It was a T4 to S1 fusion for Scheuermann kyphosis. At last follow-up (6 months), there was no loss of correction. For the second patient, only L4-5 OLIF was done rather than L4-S1 OLIF because the L5-S1 level could not be reached. In that case, the left iliac vein was adherent to the L5-S1 disc and the surgeon felt that mobilization of the iliac vein would have been too risky. It was a long fusion for adult lumbar scoliosis. At follow-up (3 years), there was a loss of correction with decreased disc space. In the last patient, approaching the L2-3 level was not possible due to a prominent rib cage, and only the L3-5 OLIF was performed. It was a T4-S1 fusion for global imbalance in a patient with Parkinson's disease. At last follow (6 months), there was no loss of correction.
The mean operative blood loss was 99.5 ± 254.0 ml for all patients, averaging 56.8 ± 131.3 ml per level. The mean blood loss was lowest for single-level approaches (53.9 ± 78.3 ml) and highest for two-level approaches (124.1 ± 319.1). Blood loss was 400 ml or less for all patients, except for two. The first patient lost 3,127 ml due to iliac vein laceration during a two-level L3-5 OLIF. The second patient lost 1,000 ml after laceration of the iliolumbar vein during a two-level L2-3 and L4-5 OLIF. In the last case, L3-4 postero-lateral interbody fusion (PLIF) had already been performed successfully.
As for mean operation time, it was 53.8 ± 18.7 minutes for all patients with an average of 32.5 ± 13.2 minutes per level. The mean operative time was lowest for single-level surgery (42.4 ± 16.8 minutes), increasing to 57.4 ± 14.8 minutes for two-level and 70.3 ± 26.4 minutes for three-level approaches. The average length of hospital stay was 7.1 ± 3.5 days for all patients. It was similar for patients undergoing single-level (6.5 ± 2.3 days), two-level (7.5 ± 4.0 days) and three-level (6.7 ± 3.4 days) procedures. However, some patients had longer hospital stays while waiting for transfer to a rehabilitation center. Due to the health system of our country (France) and to economic reasons, patients must stay a minimum of 4 nights in the hospital.
There were 19 patients with a single complication and one with two complications (). Patients with and without complications were similar with respect to age (56.2 ± 9.6 years vs. 54.1 ± 10.6 years), weight (62.3 ± 12.4 kg vs. 67.7 ± 14.7 kg), BMI (23.6 ± 3.3 kg/m2 vs. 25.0 ± 4.2 kg/m2), and the number of levels approached (1.8 ± 0.4 levels vs. 1.8 ± 0.6 levels). Of the 17 patients with more than two years of follow-up, only one had a complication consisting of left lower extremity symptoms related to iatrogenic sympathetic chain injury. The most common complication was incisional pain (2.2%), followed by lower extremity symptoms from sympathetic chain injury (1.7%). There was neither occurrence of abdominal muscle weakness nor herniation, nor retrograde ejaculation.
There were two patients with neurological deficit after left-sided L3-5 OLIF. The first patient had left L4 paresthesia and L3-4 motor weakness (grade 4 strength) presumably due to nerve stretching from restoration of disc height. For this case, surgery was uneventful and postoperative imaging did not show any misplacement of the interbody cages. The neurological deficit remained stable but she was diagnosed with pancreatic adenocarcinoma and died 4 months after the OLIF procedure. A second patient had right L4-5 paresthesia and weakness (grade 0 strength), as well as grade 3 strength in the right S1 postoperatively. Preoperatively, she already had weakness of her right lower extremity as a sequela of poliomyelitis at a young age. A CT scan showed a prominent cage of 36 mm in length at L3-4 and L4-5 compressing the dural sac contralaterally on the right side. She then underwent revision through the same incision with placement of shorter cages of 30 mm length at L3-4 and L4-5, but did not recover from her neurological injury.
One patient presented with ipsilateral weakness (grade 4 strength) in hip flexion after an L3-5 OLIF, but recovered full strength after 15 days. Due to the transient nature of the weakness, it was attributed to local pain from the surgical approach (manipulation of abdominal and/or psoas muscles). Another patient undergoing L3-5 OLIF had hypoesthesia at the upper medial aspect of the left thigh after surgery, which returned to normal, as noted at the 9-month follow-up visit. It was presumed to be caused by stretching of the ilioinguinal nerve located between internal oblique and transverse abdominal muscles at the L4-5 level near the anterior part of the iliac crest.
Two patients sustained intraoperative iliac vein laceration that was repaired primarily with non-absorbable sutures. One of these patients lost 100 ml of blood intraoperatively and presented with bilateral edema in the lower extremities postoperatively due to deep femoral venous thrombosis requiring anticoagulation treatment. Another patient had an iliolumbar vein laceration leading to a 1,000 ml blood loss that ceased after ligation. One patient decompensated from pre-existing peripheral arterial disease and presented pain in both lower extremities postoperatively due to peripheral ischemia. He improved with non-surgical treatment consisting of fluid repletion and aspirin. One patient sustained a left-sided cerebrovascular accident secondary to a patent foramen ovale associated with an anevrysm of the interatrial septum. He was treated by thrombolysis and had no residual deficit from his cerebrovascular accident.
Finally, one patient had symptomatic pseudarthrosis at the L5-S1 level after L4-S1 OLIF. She presented with persistent low back pain and underwent successful revision by posterior L5-S1 fusion followed by anterior L5-S1 fusion through a transperitoneal approach.