Lateral interbody fusion in the lumbar spine for low back pain

In a systematic review of 237 articles, the weighted averages for thigh side effects, hip flexion weakness and motor neural deficits were 26% (n=2,772), 21% (n=1,360 patients; 22 study arms) and 3% (n=1,568 patients; 14 study arms) respectively. In a systematic review of 34 studies, neurological adverse events (transient motor weakness, hypoaesthesia, transient or persistent thigh symptoms, injury to lumbosacral plexus, injury to femoral nerve) were reported. These occurred in 9% (209/2,342) of patients treated by extreme lateral interbody fusion (LIF) compared with 5% (27/544) of patients treated by anterior lumbar interbody fusion (ALIF) when Food and Drug Administration (FDA) reports were excluded (p=0.0015) and in 9% (130/1,379) of patients treated by ALIF when FDA reports were included (p=0.605). In the extreme LIF group, 43% (90/209) of the neurological adverse events resolved within 3 months of the procedure, 16% (33/209) lasted between 3 months and 2 years or throughout the last follow-up; there was no information on the remaining 41% (86/209) of complications.

Sensory deficit was reported in 27% (585/2,160) of patients treated by lateral lumbar interbody fusion (LLIF) compared with 20% (380/1,885) of patients treated by minimally-invasive transforaminal lumbar interbody fusion (MI‑LIF, p<0.0001) in a systematic review of 96 studies (n=9,714 patients). Temporary neurological deficit was reported in 9% (278/2,957) of patients treated by LLIF and 2% (30/1,349) of patients treated by MI-LIF (p<0.0001). Permanent neurological deficit was reported in 3% (62/2,525) and 1% (14/1,382) of patients respectively (p=0.002), in the same study.

Postoperative hip flexion weakness was reported in 31% (9/29) of patients treated by extreme LIF and in no patients treated by transforaminal interbody fusion (TLIF) in a randomised controlled trial (RCT) and non-randomised comparative study of 55 patients (p<0.001); all resolved within 6 months. Postoperative distal motor weakness was reported in 3.5% (1/29) and 0% (0/26) of patients respectively (p=1.00) and sensory deficit was reported in 10% (3/29) and 8% (2/26) of patients respectively (p=1.00), in the same study; all resolved within 12 months.

A partial and transient injury to the L5 nerve root during implant insertion at level L4–5 was reported in 1 patient treated by extreme LIF in a non-randomised comparative study of 208 patients; intraoperative nerve monitoring was not yet being used.

The weighted average for reoperations was 6% (n=2,080 patients; 24 study arms) in the systematic review of 237 articles. A secondary surgical procedure (revisions, supplemental fixations, reoperations) was reported in 2% (40/2,342) of patients treated by extreme LIF compared with 5% (25/544) of patients treated by ALIF when FDA reports were excluded (p=0.0002) and in 9% (121/1,379) of patients treated by ALIF when FDA reports were included (p<0.0001) in the systematic review of 34 studies.

Laceration of the abdominal aorta was reported in 1 patient in a case series of 900 patients; this was repaired through an exploratory laparotomy. Segmental vessel lacerations were reported in less than 1% (4/900) of patients in the same study; all were ligated under direct visualisation without further extension of the incision and no clinical sequelae. Major vascular injury was reported in a case report; a detachable retractor blade caused extensive damage to the iliac veins, the patient had massive blood loss and died a few weeks later from multiple organ failure secondary to septic shock. Lumbar artery pseudoaneurysm, which was successfully treated by embolisation, was reported in 1 patient in a case report.

Wound-related complications (psoas haematoma, infection) were reported in less than 1% (15/2,342) of patients treated by extreme LIF, in less than 1% (7/544) of patients treated by ALIF when FDA reports were excluded (p=0.1438) and in 2% (26/1,379) of patients treated by ALIF when FDA reports were included (p=0.00067) in the systematic review of 34 studies.

Gastrointestinal complications (ileus, gastric volvulus, bowel injury) were reported in 1% (25/2,342) of patients treated by extreme LIF, in less than 1% (3/544) of patients treated by ALIF when FDA reports were excluded (p=0.2771) and in 8% (116/1,379) of patients treated by ALIF when FDA reports were included (p<0.0001) in the systematic review of 34 studies. Ileus was reported in 7% (2/29) of patients treated by extreme LIF and in no patients treated by TLIF in the RCT and non‑randomised comparative study of 55 patients. Bowel perforation after extreme LIF was described in a case report: the patient had a temporary colostomy for 3 months before making a full recovery.

Renal complications (urinary tract infection or urinary retention) were reported in 1% (12/2,342) of patients treated by extreme LIF, in no patients treated by ALIF when FDA reports were excluded (p=0.09) and in 1% (10/1,379) of patients treated by ALIF when FDA reports were included (p=0.4214) in the systematic review of 34 studies.

Vertebral body fracture or remote compression fracture was reported in 1% (18/2,342) of patients treated by extreme LIF, in no patients treated by ALIF when FDA reports were excluded (p=0.0274) and in less than 1% (3/1,379) of patients treated by ALIF when FDA reports were included (p=0.0262) in the systematic review of 34 studies.

Hardware failure (cage subsidence or breakage, intraoperative pedicle fracture, implant bone interface failure) was reported in 1% (31/2,342) of patients treated by extreme LIF, in 3% (17/544) of patients treated by ALIF when FDA reports were excluded (p=0.0065) and in 3% (47/1,379) of patients treated by ALIF when FDA reports were included (p<0.0001) in the systematic review of 34 studies. Graft migration and graft subsidence at 24‑month follow-up were reported in 0% (0/29) and 3% (1/29) of patients treated by extreme LIF and in 5% (1/21) and 10% (2/21) of patients treated by TLIF respectively in the RCT and non‑randomised comparative study of 55 patients.

Complex regional pain syndrome was reported in 1 patient in a case report. The symptoms were treated conservatively and resolved within 8 weeks. Lumbar post-sympathectomy syndrome was reported in 5% (4/88) of patients treated by extreme LIF in the non‑randomised comparative study of 208 patients (at level L4/5 in 3 patients and at level L5/6 in 1 patient).

In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers noted that spinal cord injury was an anecdotal adverse event. They considered that kidney injury was a theoretical adverse event.