Percutaneous Unilateral Biportal Endoscopic Diskectomy and Decompression for Lumbar Degenerative Disease

11 Percutaneous Unilateral Biportal Endoscopic Diskectomy and Decompression for Lumbar Degenerative Disease

Dong Hwa Heo, Jin Hwa Eum, and Sang Kyu Son

11.1 Introduction

Traditionally, spinal endoscopic surgery was performed using a monoportal technique via one channel.1,2,3,4 One-portal spinal endoscopic surgery needs specially optimized devices, and there are surgical limitations, especially with the interlaminar approach. Recently, percutaneous endoscopic surgery has been attempted for decompression and fusion.^5,6 Although instruments for one-portal endoscopic systems have been vigorously developed, endoscopic surgical treatments for migrated disk herniation and spinal stenosis still may be difficult and have a steep learning curve.^3,4 Moreover, there are complications with endoscopic surgery.⁶ The percutaneous unilateral biportal endoscopic (UBE) approach combines the advantages of microscopic spinal surgery and endoscopic spinal surgery.^7,8 The technique is a modification and fusion of translaminar endoscopic surgery and conventional microscopic surgery.^5,7,8,9,10 The surgical procedure is similar to that for thoracoscopic or arthroscope surgery. We have used the UBE approach for the treatment of lumbar degenerative disease, such as lumbar disk herniation (including upward- and downward-migrated ruptured disks), extraforaminal ruptured disk, foraminal stenosis, and central stenosis.⁸ This chapter introduces and describes our surgical technique.

11.2 Indications

Indications for UBE surgery are similar to those for conventional open surgery and more:

• Lumbar spinal stenosis without significant instability, such as spondylolisthesis

• Central lumbar herniated disk: Upward migration, downward migration, calcified disk

• Extraforaminal and foraminal lumbar disk herniation

• Recurrent lumbar disk herniation

• Foraminal stenosis

Fig. 11.1 Biportal endoscopic spine surgery uses a 0° arthroscope.

11.3 Equipment

All standard devices for open spinal surgery are available for UBE surgery. The 0° endoscope is an arthroscopic system that is used in knee or shoulder arthroscopic surgeries (Fig. 11.1). For exposing the laminar and interlaminar space, a specially designed periosteal dissector and serial dilators are used (Fig. 11.2). However, the specialized instruments can be replaced with other serial dilators and a small periosteal dissector or elevator. For the dissection of soft tissue and bleeding control, we use radiofrequency probes that are already used in arthroscopic surgery or single-portal spinal endoscopic surgery. For removal of bony structures, such as in laminectomy and foraminotomy, we prefer the one-sided protected drill (Fig. 11.3). All types of arthroscopic and endoscopic drill systems are available for biportal endoscopic surgery. For the continuous saline irrigation, we prefer a pressure-pump irrigation system. Simple water-pressure control using the height of the saline bag on the fluid stand is also possible.

Fig. 11.2 Periosteal dissector and serial dilator for biportal endoscopic surgery.

Fig. 11.3 A one-side protected drill is used for laminotomy and facetectomy.

Fig. 11.4 Intraoperative view of percutaneous unilateral biportal endoscopic surgery for the lumbar spine.

Fig. 11.5 (a) Incision points of two portals for central stenosis or herniated disk. (b) The cranial portal is the endoscopic channel, and the caudal portal is the working channel.

• Arthroscope

• Periosteal dissector

• Serial dilators

• Standard laminectomy instruments, such as hook dissectors, double-ended dissector, Kerrison punches, and pituitary forceps

• 3.5-mm spherical bur (ConmedLinvatec, Utica, NY), 0° 4-mm diameter arthroscope (ConmedLinvatec, Utica, NY)

• Bipolar flexible radiofrequency probe (Ellman Trigger-Flex Probe, Ellman International, NY)

• VAPR radiofrequency electrode (DePuy Mitec, Warsaw, IN)

• Pressure-pump irrigation system (Smith & Nephew, Inc., Memphis, Tennessee)

11.4 Surgical Procedure

UBE surgery is similar to an arthroscopic or a thoracoscopic operation (Fig. 11.4). The procedure is performed under general or epidural anesthesia. The patient is placed on a radiolucent operating table for fluoroscopic guidance. We prefer a Wilson frame or a Jackson operating table to minimize abdominal pressure in the prone position. A waterproof surgical drape is applied due to continuous saline irrigation.

11.4.1 Percutaneous Unilateral Biportal Endoscopic Diskectomy for Lumbar Disk Herniation (Video 11.1 and Video 11.2)

Two portals are made: one portal is used for continuous irrigation and endoscopic viewing, and the other portal is used for insertion and manipulation of the instruments used in diskectomy and decompression procedures (e.g., laminotomy and removal of ligamentum flavum; Fig. 11.4).⁸

The operation level is identified under C-arm fluoroscopic guidance. The exact target point is the intersection of the lower lamina margin and a line 1 cm lateral to the spinous process. Endoscopic and working portals are made ipsilaterally with the ruptured disk. A 1- to 1.5-cm skin incision (caudal portal) is made vertically above the target point (Fig. 11.5). We try to make the two portals into loose connective tissue between fascicles of the multifidus muscle (multifidus triangle, Fig. 11.6). A K-wire is introduced through the skin incision in the direction of the target point. Serial dilators are inserted toward the lower lamina.

Fig. 11.6 The multifidus triangle is an area of loose connective tissue between fascicles of the multifidus muscle. Two portals are made in the triangle.

Following removal of the dilators, a specially designed dissector (Fig. 11.2) is moved to the lower lamina. Interlaminar soft tissue is dissected laterally to the medial margin of the facet capsule. A second 0.5- to 1-cm incision for the endoscope (cranial portal) is made, ~ 2 to 3 cm above the upper edge of the first caudal skin incision (Fig. 11.5). A 0° endoscope is inserted through the cranial portal after insertion of the cannula. A saline irrigation pump is connected to the endoscope and set to a pressure of 20 to 30 mm Hg (height pressure control: 150–170 cm) during the procedure; the continuous flow of saline irrigation should clear the endoscopic surgical view and prevent bleeding in the operative field. The irrigation fluid flows from the scope portal to the working portal. Surgical instruments are inserted through the caudal working portal.

After triangulation of the endoscope and instruments (Fig. 11.7), radiofrequency probes are used for debridement of the soft tissue overlying the lamina and ligamentum flavum. If lower laminar and interlaminar spaces are completely exposed, the surgical endoscopic view is clearer due to expansion of holding space for irrigation fluid. Following complete exposure of the lower lamina and ligamentum flavum in the target interlaminar space, ipsilateral partial laminotomy is performed under magnified endoscopic vision, with a 3.5-mm soft tissue protected drill and Kerrison punches (Video 11.1). The endoscopic anatomical view is very similar to the microscopic view in posterior laminotomy and diskectomy. The ipsilateral ligamentum flavum is removed until full identification of the lateral border of the nerve root. The upper border of the lower lamina and medial border of the facet are removed (medial facetectomy) for the ipsilateral foraminotomy as needed. If there are particles from an upward- or downward-migrated ruptured disk, a more extended unilateral laminectomy of the upper or lower lamina is achieved for complete removal of the particles. According to the surgeon’s preference, an additional annular incision and diskectomy can be performed after removal of the ruptured disk particles. Percutaneous unilateral biportal endoscopic diskectomy (UBED) is similar to conventional micro-diskectomy.