Tubular Endoscopic Lumbar Hemilaminectomy and Foraminotomy

16 Tubular Endoscopic Lumbar Hemilaminectomy and Foraminotomy

Benedikt W. Burkhardt and Joachim M. Oertel

16.1 Introduction

Lumbar canal stenosis and lumbar disk herniation may cause claudication or lumbar radiopathy with pain radiating down the extremities in a dermatomal distribution, sensory deficits, and loss of motor strength. It represents one of the most common symptoms that spine surgeons have to deal with. If conservative treatment is unsuccessful, surgery should be considered for decompression of the neuronal structures. Lumbar diskectomy and laminoforaminotomy are the most commonly performed surgical approaches in surgery for pathologies in this region.1 The traditional open approach results in damage to the paraspinal back muscles due to tissue dissection, as well as damage to the midline structures. The surgical approach was further developed by using an operating microscope, which offered better illumination of the surgical field, and consequently resulted in “mini-open” approaches in the 1970s. However, significant iatrogenic trauma was still associated with the technique.^2,3 In the early 1990s, tubular dilation systems were used for the first time in lumbar spine surgery. The idea was to dilate the muscle instead of dissecting it from the osseous structures.

Foley and Smith first introduced a system that enables the surgeon to perform lumbar disk surgery in standard open bimanual microsurgical technique via microscopic and/or additionally endoscopic visualization in 1997. This technique, using microsurgical instruments and additional endoscopic visualization, became known as microendoscopic diskectomy (MED). The technique offers the advantages of less muscle damage, decreased postoperative pain, faster postoperative recovery, and shorter in-hospital stay.^4,5,6,7,8 Furthermore, the clinical outcome after surgery via a tubular system is comparable to the standard microsurgical technique. The authors have demonstrated that several degenerative disorders of the cervical and lumbar spine can be treated effrectively via microendoscopic technique.^{9,10,11,12,13,14,15} This chapter describes the technique of endoscopic lumbar hemilaminectomy and foraminotomy using a tubular endoscopic system (EasyGO!, Karl Storz GmbH & Co. KG, Tuttlingen, Germany).^16,17

16.2 Indications

• Ipsilateral mono- and bisegmental lumbar canal stenosis

• Bilateral mono- and bisegmental lumbar canal stenosis

• Lateral recess stenosis with or without subligamentous disk protrusion

• Hypertrophic facet joint with subsequent lumbar lateral recess or foraminal stenosis

• Bony foraminal stenosis and lumbar synovial cyst

16.3 Exclusion Criteria

• Spinal instability

16.4 Case Presentation

• A 65-year-old man presented with a history of mild low back pain. For 6 months he had suffered from spinal claudication with left-sided radiating leg pain. The leg pain was scored 7/10 on the visual analog scale. Walking distance had decreased to 50 to 100 m. Conservative treatment was unsuccessful.

• The preoperative examination showed foot drop (⅘ paresis) and quadriceps weakness (⅘ paresis) on the left side.

• Post-myelogram CT showed a central spinal stenosis due to hypertrophy of the ligamentum flavum in segments L3–L4 and L4–L5 (Fig. 16.1)

16.5 Preoperative Plan

• Careful analysis of the ideal surgical approach is done based on preoperative imaging data (MRI, CT, post-myelogram CT).

Fig. 16.1 (a) Preoperative sagittal and axial post-myelogram CT scans. The dural sac (white stars) is severely compressed and the contrast agent is blocked (arrow) in segment L3–L4 and upward. (b) Preoperative sagittal and axial post-myelogram CT scans shows the hypertrophied ligamentum flavum (white stars) and the compressed dural sac (white arrow, right picture).

Fig. 16.2 (a,b,c) Removal of remnant connective tissue and display of lamina with grasping forceps and bipolar cautery. (d) Identification of the lamina (white stars). (e,f) Subsequent thinning out of the lamina by diamond drill. For orientation: the upper part of each image is medial, the lower part of each image lateral. Left is cranial, right caudal.

Fig. 16.3 (a) Bipolar cautery is used for hemostasis (arrow). (b,c,d) The hemilaminectomy is performed by subsequent thinning out of the lamina with the diamond drill and Kerrison punch. (d) The area of hemilaminectomy is marked with stars. (e) For a contralateral decompression by undercutting, the base of the spinous process has to be identified (stars). (f) Subsequently, the ligamentum flavum (arrows) is dissected from the dural sac with a microhook. For orientation: the upper part of each image is medial, the lower part of each image lateral. Left is cranial, right caudal.