Percutaneous Endoscopic Lumbar Diskectomy

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  In 1934, Mixter and Barr conducted exploratory laminectomy for radicular pain. They reported 19 surgical cases of lumbar, thoracic, and cervical prolapse of nucleus pulposus or fractured nucleus that correlated with the etiology of sciatica and radicular pain.1

  
  
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  Hult first introduced the concept of indirect spinal canal decompression by nucleotomy using the anterolateral abdominal extraperitoneal approach in 1951.2

  
  
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  In 1964 a true paradigm shift began in the minimally invasive approach to the lumbar disk when Lyman Smith introduced chemoneucleolysis through a percutaneous injection of chymopapain to a patient with sciatica to hydrolyze the herniated nucleus pulposus. This approach was later abandoned by most surgeons due to its untoward side effects such as transverse myelitis.3

  
  
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  In January 1973, Kambin initiated percutaneous indirect spinal canal decompression by nucleotomy using the Craig cannula through a posterolateral extracanal nonvisualized approach.4

  
  
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  Hijikata et al first introduced a stand-alone, nonvisualized posterolateral percutaneous nucleotomy in 1975.5

  
  
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  Kambin and Gellman reported a 72% success rate for 136 patients treated with a percutaneous lateral technique similar to the method adopted by Hijikata.6 This success was due to the reduction of intradiskal pressure by fenestration of the outer annulus.

  
  
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  In 1983, William Friedman introduced the direct lateral approach for percutaneous nucleotomy, which was associated with a higher risk of bowel injury.7

  
  
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  In 1983, Forst and Hausmann first reported introduction of a modified arthroscope into the intervertebral disk space.8

  
  
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  A nonvisualized motorized aspiration nucleotomy shaver with a 2.8-mm diameter was introduced by Onik et al in 1985, along with a technique termed automated percutaneous nucleotomy.9 Present-day nucleotomes are the more sophisticated versions of this motorized shaver ( Figs. 1.1 and 1.2 ).

  
  
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  Kambin published the first intraoperative diskoscopic views of herniated nucleus pulposus (HNP) in 1988. In his later publications, Kambin et al further propagated the importance of diskoscopic visualization of the peri-annular space.10

  
  
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  In 1989, Schreiber et al used a biportal approach with a diskoscope to inject a vital dye, indigo carmine, to stain abnormal nucleus and annular fissures.11

  
  
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  In 1990, Kambin described and illustrated the triangular working zone.4 The safe zone is bordered anteriorly by the exiting root, inferiorly by the end plate of the lower lumbar segment, posteriorly by the superior articular process of the inferior vertebra, and medially by the traversing nerve root ( Fig. 1.3 ). Before description of this safe zone, the instruments inserted posterolaterally were of very small size to prevent iatrogenic injury to the nerve root. This presented the option of introducing larger instruments without injuring the exiting nerve and opened the door for more sophisticated endoscopes with larger working channels. • In 1993, Mayer and Brock reported an endoscopic technique, similar to Schreiber’s biportal approach, using an angled lens scope concentrating the vision dorsally around the annular tear.12

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  Foley et al, in 1999, presented their endoscopic working channel approach to far-lateral disk herniations.13

  
  
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  Mathews in 199614 and Ditsworth in 199815 reported the success of the foraminoscopic approach. This opened the era of transforaminal endoscopic surgery for lumbar disk herniations.14

  
  
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  The surgical endoscopic technique for the decompression of nerve roots compromised by lateral recess stenosis by annulectomy and osteophytectomy using mechanical tools (forceps and trephines) and 0- and 30-degree scopes was reported by Kambin and Zhou in 1996.16

  
  
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  In 1997, Tsou and Yeung introduced a rigid rod-lens, integrated, multichannel, wide-angled endoscope.17

  
  
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  In 2001, Knight et al, described the technique of endoscopic foraminoplasty using a side-firing holmium: yttrium-aluminum-garnet (Ho-YAG) laser.18 They concluded that endoscopic laser foraminoplasty provides an excellent means of neural mobilization as well as of exploring the extraforaminal zone and foramen.

  
  
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  By 2002, intradiskal electrothermal annuloplasty and newly designed lasers were being advocated for percutaneous thermal annuloplasty and nucleoplasty for patients with low back pain.19

  
  
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  Yeung and Tsou, in 2002, retrospectively evaluated the effcacy of endoscopic diskectomy in 307 patients and reported it to be comparable with conventional open surgery.20

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  In the same year, Tsou and Yeung described their surgical outcomes in 219 patients with intracanal noncontained lumbar disk herniations with at least 1-year follow-up. They concluded that noncontained intracanal lumbar disk herniation fragments are accessible using a transforaminal endoscopic technique with a 91.2% clinical success rate.17

  
  
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  In 2003, Yeung devised a standardized method for transforaminal endoscopic surgery, the Yeung Endoscopic Spine System (YESS) (Richard Wolf Medical Instruments Corp., Vernon Hills, Illinois). The protocol includes the following: a protocol for optimal instrument placement, evocative diskography, selective endoscopic diskectomy, thermal diskoplasty and annuloplasty, endoscopic foraminoplasty, accessing the epidural space in the axilla between exiting and traversing nerve roots, and partially resecting the posterior annulus to access the underside of the herniated mass if needed. • Tsou et al described posterolateral transforaminal selective endoscopic diskectomy and bipolar radiofrequency thermal annuloplasty for chronic lumbar diskogenic pain (CLDP) in 2004.22 In contrast to other percutaneous procedures for CLDP, this technique allowed direct visualization and targeting of disk nucleus and annular fissures. The results, however, did not demonstrate a significant clinical benefit.

  
  
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  Ruetten et al (2005) indicated that the usual transforaminal access is posterolateral and is associated with problems in reaching the epidural space directly with unhindered vision. This complication prevents sufficient decompression in lumbar disk herniations. To overcome this technical stalemate, they presented an extreme lateral access using the full endoscopic uniportal transforaminal approach.23

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  Schubert and Hoogland in 2005 presented their technique to remove a sequestrated lumbar disk by endoscopic transforaminal nucleotomy with foraminoplasty using reamers. They reported 95.3% success.24

  
  
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  In 2006, Lee et al, studied the failed cases of percutaneous endoscopic lumbar diskectomy and came to the conclusion that patients with high-canal compromise and high-grade migration are at a higher risk for a remnant fragment leading to failure.25

  
  
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  In the same year, Hoogland et al presented their prospective, randomized study involving 280 consecutive cases of lumbar disk herniation managed either by endoscopy alone or an endoscopic diskectomy combined with an intradiskal injection of low-dose (1000-U) chymopapain.26 They concluded that a high percentage of patient satisfaction could be obtained with a posterior lateral endoscopic diskectomy for lumbar disk herniation.

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  In 2007, Choi et al reported a series of 41 patients with a soft extraforaminal disk herniation treated with their new extraforaminal targeted fragmentectomy technique and reported a 92% success rate.27 In their technique, they medialized the skin entry point with a steeper angle ( Fig. 1.4 ).

  
  
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  In 2007, Lee et al reported 91.8% satisfactory results in downmigrated disks, 88.9% in upmigrated, 97.4% in near-migrated disk, and 78.9% in far-migrated disk using their classification for migrated disks.28

  
  
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  Ruetten et al reported their results of 232 patients treated with full-endoscopic transforaminal diskectomy in 2007 using their newly developed 4.2-mm working channel endoscope and corresponding instruments.29 They found the results were comparable to open disk surgery.

  
  
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  Recently, endoscopic lumbar nerve root decompression has progressed from nonvisualized indirect central nucleotomy to direct excision of noncontained extruded disk fragment. The concept of decompressing the nerve root has grown in sophistication from the original central disk debulking to a precise targeted fragmentectomy ( Figs. 1.5 and 1.6 ).