Iliac arterial injury following anterior lumbar surgery: a case report

Anterior spine surgery for the treatment of complex spine pathology: a state-of-the-art review

The use of anterior spinal surgery for the treatment of spinal pathology has experienced a dramatic increase over the past decade. Long relegated to treat complicated anterior pathologies it has returned to mainstream spine surgery techniques for all types of conditions, providing a significant boost to the spine surgeons' armamentarium to address a wide variety of types of spinal diseases more effectively. Anterior surgery is useful whenever there is significant spinal pathology that requires direct visualization of the anterior vertebral column to best restore spinal alignment, structural integrity and neurologic function. These pathologies include spinal deformities, tumors, burst fractures, infections, vertebral avascular necrosis, pseudoarthrosis and other miscellaneous indications. Currently available approaches to the spine include transabdominal, paramedian retroperitoneal, lateral oblique retroperitoneal, thoracotomy, and thoracolumbar extensile. Most of the lumbar approaches are now done through a muscle splitting, minimalistic approach that has decreased their morbidity or more recently via tubular approaches, such as lateral lumbar interbody fusions or other ante-psoas approaches. New retractors, instrumentation, hyperlordotic implants, approved biologics and even image guidance for disc preparation and precise implant placement are all recent advances that will hopefully improve surgical outcomes in patients following anterior spinal surgery. Most importantly, these approaches require added expertise and training with a dedicated team consisting of an anteriorly trained spine surgeon working simultaneously with a dedicated vascular surgeon to ensure maximum safety and superior patient outcomes. This state of the review is dedicated to familiarizing practicing spine surgeons with the most commonly used anterior spinal approaches along with cutting-edge instrumentation and fusion techniques to improve their options for the treatment of difficult spinal pathologies.

Brief intraoperative heparinization and blood loss in anterior lumbar spine surgery

OBJECT

The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. Intraoperative heparin can be administered to prevent thrombosis; however, there is a concern that this will increase the procedural blood loss. The aim of this study was to examine whether intraoperative heparin can be administered without increasing blood loss in anterior lumbar spine surgery.

METHODS

A prospective study of consecutive anterior approaches for lumbar spine surgery was performed between January 2009 and June 2014 by a single vascular surgeon and a single spine surgeon. Patients underwent an anterior lumbar interbody fusion (ALIF) at L4-5 and/or L5-S1, a total disc replacement (TDR) at L4-5 and/or L5-S1, or a hybrid procedure with a TDR at L4-5 and an ALIF at L5-S1. Heparin was administered intravenously when arterial flow to the lower limbs was interrupted during the procedure. Heparin was usually reversed on removal of the causative retraction.

RESULTS

The cohort consisted of 188 patients with a mean age of 41.7 years; 96 (51.1%) were male. Eighty-four patients (44.7%) had an ALIF, 57 (30.3%) had a TDR, and 47 (25.0%) had a hybrid operation with a TDR at L4-5 and an ALIF at L5-S1. One hundred thirty-four patients (71.3%) underwent a single-level procedure (26.9% L4-5 and 73.1% L5-S1) and 54 (28.7%) underwent a 2-level procedure (L4-5 and L5-S1). Seventy-two patients (38.3%) received heparinization intraoperatively. Heparin was predominantly administered during hybrid operations (68.1%), 2-level procedures (70.4%), and procedures involving the L4-5 level (80.6%). There were no intraoperative ischemic vascular complications reported in this series. There was 1 postoperative deep venous thrombosis. The overall mean estimated blood loss (EBL) for the heparin group (389.7 ml) was significantly higher than for the nonheparin group (160.5 ml) (p < 0.0001). However, when all variables were analyzed with multiple linear regression, only the prosthesis used and level treated were found to be significant in blood loss (p < 0.05). The highest blood loss occurred in hybrid procedures (448.1 ml), followed by TDR (302.5 ml) and ALIF (99.7 ml). There were statistically significant differences between the EBL during ALIF compared with TDR and hybrid (p < 0.0001), but not between TDR and hybrid. The L4-5 level was associated with significantly higher blood loss (384.9 ml) compared with L5-S1 (111.4 ml) (p < 0.0001).

CONCLUSIONS

During an anterior exposure for lumbar spine surgery, the administration of heparin does not significantly increase blood loss. The prosthesis used and level treated were found to significantly increase blood loss, with TDR and the L4-5 level having greater blood loss compared with ALIF and L5-S1, respectively. Heparin can be administered safely to help prevent thrombotic intraoperative vascular complications without increasing blood loss.