Short-Term Lumbar Plexus Morbidity Related to Mini-Open Retroperitoneal Transpsoas Corpectomy

Aims: Lumbar plexus injury is a well-described complication of retroperitoneal transpsoas approach to the lumbar spine. The rate of lumbar plexopathy seems to be underestimated and underreported in literature. However, there is no specific data available concerning plexopathies following retroperitoneal transpsoas corpectomies. Corpectomies demand a wide surgical corridor and significant retraction on the psoas fibers and require surgical manipulation of lumbar plexus branches.

Methods: We reviewed the reports of 17 consecutive patients, who had undergone a left-sided mini-open retroperitoneal transpsoas corpectomy for traumatic and osteoporotic fractures between 2005 and 2012. We retrospectively analyzed the pre- and postoperative neurological status and followed the patient’s clinical condition at 6 months. Lumbar plexus integrity was assessed by a close clinical neurological examination. Sensory deficits were assessed and classified according to Ahmadian et al¹ (sensory dermal zone [SDZ I]: subcostal, iliohypogastric, ilioinguinal, genitofemoral nerves; II: lateral femoral cutaneous nerve; III: femoral and saphenous nerve; and IV: obturator nerve).

Results: Fourteen patients (82%) had a preoperative neurological deficit related to the fracture. Lumbar vertebrae involved were L2 (6 patients), L3 (8 patients), and L4 (3 patients). The fractures were either traumatic (14) or osteoporotic (3). At discharge, 8/17 patients (47%) had new sensory deficits attributable to nerve manipulation (SDZ I: 2, II: 3, III: 3, IV: 0). Two patients presented psoas muscle weakness due to the surgical access. One patient could not be assessed due to pre-existing motor and sensory deficits related to the fracture. The 6 months follow-up showed the persistence of surgery-related sensory deficits in all the cases. N = 1/2 patients recovered from psoas weakness. One patient, who was already presenting SDZ III disturbance after the first surgery, underwent a second surgery because of a cage displacement.

Conclusion: Our findings suggest that mini-open retroperitoneal transpsoas corpectomy involves a relatively high risk of lumbar plexopathy, mostly confined to sensory deficits. Sensory deficits tend to be unchanged at 6 months and motor deficits due to the surgical route are rare. More clinical trials with long-term follow-up are necessary to assess lumbar plexus injuries, recovery rates, and their impact on patients’ quality of life.