Complications: Lumbosacral Fusion
Lumbosacral Fusion: Cages, Dowels, Pedicle Screws: Part 5
The majority of complications associated with cylindrical anterior interbody fusion devices are a result of the operative approach, as opposed to specific device-related problems.64, 84 These include autograft harvest morbidity, postoperative hernias,48 bowel obstruction47 (which can occur after violation of the peritoneum during a retroperitoneal approach), postoperative ileus, iliac venous thrombosis, 12, 14, 36 urological injury60 (1.4%), and retrograde ejaculation. The later has been reported to occur in 0.4-2.0% of male patients. 14, 60, 90 It is due to injury of the autonomic superior hypogastric plexus in the retroperitoneal space, which normally mediates closure of the bladder neck during ejaculation. Major vascular (venous or arterial) complications have been reported in 0.5-4.0% of ALIF procedures. 57, 60, 84, 85 Particularly at risk is the left iliolumbar vein, which can be avulsed during mobilization of the left common iliac vein, in procedures at the L4-L5 interspace. 3
Device-related complications of anterior interbody fusion procedures consist primarily of cage malposition, migration, and iatrogenic disc herniation. Laterally positioned titanium cages or threaded cortical bone dowels can cause direct foraminal nerve root compression and radiculopathy. 39, 64, 65, 73 Often, this can be a result of the surgeon failing to accurately identify the anterior vertebral anatomic midline, prior to inserting the paired interbody devices. Similarly, placement of the threaded interbody device into the interspace too far lateral can result in an iatrogenic disc herniation, causing compression of the exiting root in the manner of a "far lateral" disc herniation. 65 Anterior interbody implant migration has been reported in 2.3% of patients, with 1.2% of the total requiring re-operation. 60 Dural complications associated with the anterior placement of threaded interbody devices60, 64, 83 have not been reported. The PLIF technique, however, by the very nature of its dorsal approach, is associated with a 10% incidence of dural injury 60 and can lead to paresthesia from nerve root retraction.
Laparoscopic anterior interbody cage insertion has been associated with a higher rate of device-related complications as compared to the open technique, largely due to postoperative disc herniation. 84 Utilizing laparoscopic transperitoneal techniques, some authors have reported somewhat longer operative times, but significantly less blood loss and shorter hospital stays as compared to open ALIF procedures with threaded interbody fusion devices. 84, 85 Usually, the L5-S1 interspace is caudal to the bifurcation of the common iliac vessels, requiring minimal mobilization (except in instances of lumbosacral transitional vertebrae). A recent prospective study of threaded interbody device procedures performed at the L4-L5 level found no difference in operative time, blood loss, or length of stay when comparing laparoscopic transperitoneal ALIF to mini-open ALIF. 102 The authors, however, found a significantly higher rate of complications in the laparoscopic ALIF group (25% versus 4%). Furthermore, adequate exposure was attained in only 84% of the laparoscopic cases while in 100% of the mini-open ALIFs two cages could be inserted.