The far lateral approach to lumbar disc herniations

Minimally invasive far lateral microendoscopic discectomy for extraforaminal disc herniation at the lumbosacral junction: cadaveric dissection and technical case report

BACKGROUND CONTEXT

Extraforaminal lumbar disc herniations (ELDHs) at the lumbosacral junction are an uncommon cause of L5 radiculopathy. The surgical anatomy of the extraforaminal space at L5-S1 is uniquely challenging for the various open surgical approaches that have been described for ELDHs in general. Reports specifically describing minimally invasive surgical approaches to lumbosacral ELDHs are lacking.

PURPOSE

To report the novel use of a far lateral microendoscopic (FLMED) approach to lumbosacral ELDH. To better define the unique anatomical features of extraforaminal approaches to the lumbosacral junction as they apply to minimal access techniques.

STUDY DESIGN/SETTING

A cadaveric investigation and clinical case were performed at a single institution. A thorough review of the literature was conducted.

PATIENT SAMPLE

A single patient with an extraforaminal disc herniation at the lumbosacral junction underwent evaluation and surgery.

OUTCOME MEASURES

The patient's self-reported pain levels were documented. Physiologic outcome was judged on pre- and postoperative motor and sensory examinations. Functional capacity was assessed by work status and ability to perform activities of daily living.

METHODS

FLMED was performed in two fresh human cadavers at the lumbosacral junction. Qualitative assessments of the surgical anatomy were made, and intraoperative fluoroscopy and endoscopic photographs were obtained to document the findings. A patient with refractory pain and sensorimotor deficits from compression of the L5 nerve root by an ELDH underwent FLMED. The literature was carefully reviewed for the epidemiology of ELDHs at the lumbosacral junction and the surgical techniques used to treat them.

RESULTS

The posterolateral surgical corridor to the lumbosacral disc was consistently constrained by the sacral ala and to a lesser extent the lateral facet and L5 transverse process. Resection of the superior ala exposed the exiting nerve root and provided ample access to the disc. In the clinical case, the patient enjoyed immediate pain relief, was discharged in 3 hours, and returned to full work and social activities. Follow-up neurological examination revealed no sensory or motor deficit.

CONCLUSIONS

FLMED offers a safe and efficacious approach to ELDHs at the lumbosacral junction by combining satisfactory visualization for adequate resection of the sacral ala with the benefits of reduced tissue injury and faster recovery times that accompany minimally invasive techniques.

Far-lateral lumbar disc herniation: the microsurgical transmuscular approach

Intra- and extraforaminal disc herniations can be treated via a lateral approach. The far-lateral approach is a muscle-splitting approach that allows surgeons to reach the disc herniation without any facet bone removal. The target of the surgical exposure is the isthmus. Good knowledge of the anatomic features of the intervertebral foramen and intertransverse space is mandatory. The transmuscular approach is discussed. We provide illustrations and a video to emphasize some operative aspects.

Long-term follow up of patients surgically treated by the far-lateral approach for foraminal and extraforaminal lumbar disc herniations

OBJECT

This study was undertaken to evaluate the long-term benefit in 202 patients who were surgically treated via a microsurgical far-lateral approach for foraminal or extraforaminal lumbar disc herniations.

METHODS

All patients underwent surgery at the authors' institute since 1987 and represented 6.5% of all lumbar spinal disc surgeries. There were 67 women and 135 men who ranged in age from 19 to 78 years (mean age 58 years). All patients had unilateral leg pain due to lumbar disc herniations into or lateral to the lateral interpedicular compartment. One patient underwent surgery at the L1-2 level, nine at L2-3, 48 at L3-4, 86 at L4-5, and 58 at the L5-S1 level. The mean follow-up period was 50 months (range 12-120 months). Outcome was defined as excellent (no pain), good (some back pain), fair (moderate radiculopathy), and poor (unchanged or worse) based on Macnab classification. Overall, excellent and good results were achieved in 62 (31%) and 85 (42%) patients, respectively, and fair and poor results in 40 (20%) and 15 (7%) patients, respectively. Of 11 recurrent disc herniations, four presented in an extreme-lateral position, five in a paramedian location, and two on the contralateral side. There were three minor complications related to surgery, seven general complications, and no case of spinal instability.

CONCLUSIONS

The far-lateral approach is a safe, effective procedure that avoids the risk of secondary spinal instability.