Introduction

The aging spine typically begins with disc degeneration and annular dehiscence, followed by transfer of loads from the anterior spinal column to the facets. This may produce discogenic pain and axial back pain, resulting in segmental instability with resultant deformity. If the condition becomes painful, and nonsurgical treatment is not effective, traditional surgical treatment has been limited to diskectomy and fusion. Though diskectomy has been shown to be beneficial by the SPORT¹ study, the long-term cost-effectiveness of fusion is questioned. Traditional spine surgery to treat painful degenerative disc disease such as with herniated discs, spondylolisthesis, central spinal stenosis, and neuroforaminal stenosis encompasses many different techniques. Surgical treatment, however, often results in a “failed back surgery syndrome” (FBSS) with limited success for subsequent salvage procedures. Newer minimally invasive techniques, in skilled and experienced hands, when approaching the pathology along natural muscle and tissue planes opens the door to earlier and a greater number of minimally invasive surgical options for the painful, aging spine without excessive concern about the paradoxical effects of surgery. The concept of “endoscopic surgical pain management” is addressed in this chapter, based on the senior author’s (ATY) 20-year experience using his percutaneous endoscopic transforaminal surgical technique described as the YESS (Yeung Endoscopic Spine Surgery) procedure.

The YESS procedure eliminates the pain generator causing the pain syndrome, not just “masking” the pain with therapeutic injections. The approach accomplishes disc decompression by “selectively” removing degenerative nucleus, sealing and closing annular tears, decompressing spinal nerves, ablating nerves and inflammatory tissue contributing to discogenic and axial back pain, and surgically removing a wide spectrum of disc herniations. In more advanced stages, lumbar spondylolysis and isthmic and degenerative spondylolisthesis can also be addressed surgically. This brief overview provides examples of conditions that the senior author has treated endoscopically with minimal surgical morbidity, in contrast with the much more invasive traditional option. The reader is directed to the published references for more detailed information on the evolution of this new minimally invasive and innovative technique.^2–15

Traditional surgical correction in the aging spine usually involves open decompression, fixation, and fusion techniques. The percentage of fusion surgeries for these conditions as a whole has increased dramatically in the United States over the past few decades. Between 1990 and 2001, lumbar fusion surgery increased 220%.¹⁶ A recent article by Tosteson and colleagues,¹⁷ examining the data from the SPORT trial, concluded that even for degenerative spondylolisthesis surgery (decompression and fusion) is not a cost-effective procedure, when examined over a 2-year period. The importance of this data is that it emphasizes the need to better identify the source of back pain and sciatica, possibly earlier treatment, and more thorough study of the complex innervations of the spine in the foramen (Figure 64-1A-C). This area, known as the “hidden zone” of MacNab, holds the answer to the effectiveness of foraminal decompression and ablation of foraminal nerves in the treatment of discogenic and facet pain. It may have an impact on health care reform that seeks to reduce the cost of care, because over 100 billion dollars a year is spent on back pain in the United States, most of it being spent on nonsurgical treatment such as physical therapy, interventional pain management, and over-the-counter and prescription drugs. We also need to reduce the need for fusion as a surgical solution for pain. This can be accomplished if we are able to not only demonstrate the efficacy and cost-effectiveness of endoscopic surgical pain management, but help establish a new subspecialty in endoscopic surgical pain management, because it requires special training to acquire proficiency.

FIGURE 64-1 A, Fresh cadaver dissection of dorsal and foraminal anatomy showing the relationship of the disc annulus, spinal nerves, facets, and lamina dictating surgical access. Normal left foraminal anatomy L2-S1. Blue: hubbed needles are inserted into the disc space in the foramen accessing the posterolateral quadrant of the disk. Note the furcal nerve branch at L4-L5. The epidural space can be reached with a far lateral trajectory and/or by removing the ventral facet with trephines, lasers, or endoscopic high-speed diamond burrs. All soft tissue has been stripped from the transverse processes, including dorsal ramus innervation of the dorsal column. The intertransverse ligament covering the exiting nerves in the foramen has been stripped away. B, Facet innervation and the relationship of the transverse process, the interspinous ligament, and the exiting nerve in the foramen. The right exiting nerve at L3-L4 exhibits a furcal nerve branch traversing the foramen in the far lateral quadrant of the L3-L4 disc annulus. Furcal nerves are the myelinated branches of normal spinal nerves (usually the exiting nerve), commonly seen endoscopically in the foramen. When stimulated or cut, these nerves can cause dysesthesia and react like the parent spinal nerve. It does not respond like the main nerve because it is usually too small to be detected by continuous intraoperative electromyography or radicular pain reported by the patient. The endoscopic surgeon should take care to recognize and not injure these furcal nerves if they are more than 1 mm in diameter, but they cannot always be avoided. Dysesthesia, immediately postoperative or delayed, is readily treated by transforaminal epidural blocks combined with sympathetic blocks. Furcal nerves can be responsible for sciatica that is seemingly out of proportion to what is suggested by relatively normal MRI appearance, and may be part of the sciatica reported preoperatively. Note also the proximity of the intermediate and lateral branches of the dorsal ramus on the cephalic edge of the transverse process at L3. The dorsal ramus sends a medial branch that crosses the transverse process on the way to innervate the facet joint above and below the disc level. Irritation of the lateral branch, when irritated, can cause muscle spasm and an involuntary list. C, Dorsal ramus innovation of L3, L4, and L5 facets. The dorsal ramus emanating from the origin of the spinal nerve sends off medial, intermediate, and lateral branches to innervate the facets and the dorsal muscle column. The interspinous ligament has been removed to expose the dorsal ramus. It is found just ventral to the intertransverse ligament and can irritate the exiting nerve and its dorsal root ganglion. This poorly studied nerve can be responsible for severe chronic axial back pain associated with a degenerating disc exhibiting grade IV and V far lateral annular tears. Back pain, not just sciatica, caused by disc protrusions and annular tears can be explained by irritation of the dorsal ramus, not just the spinal nerves. Selective endoscopic diskectomy and thermal annuloplasty can reduce axial back pain and sciatica, and Intradiscal Electrothermic Therapy (IDET) cannot reach these nerves! Endoscopic rhizotomy of the branches of the dorsal ramus has shown to be a very effective means of decreasing chronic severe axial back pain.

Understanding chronic, surgically treatable back pain begins with understanding common lumbar pain. Cadaver microdissection of the nerves in the foramen reveals an extensive network of nerves arising from the spinal cord, splitting into the dorsal and ventral rami before exiting the foramen as the spinal nerve. A ramus communicans connects with the sinuvertebral nerves innervating the annulus. When there is an inflammatory response to annular tears with the development of an inflammatory membrane, the subsequent neo-neurogenesis and angiogenesis response contributes to pain that is not detected by imaging studies currently available. Better soft tissue imaging and imaging of chemical changes in the spine may help. We traditionally only grossly see the traversing and exiting spinal nerves as surgeons, and routinely fail to recognize and miss the relatively common furcal nerve, or the dorsal ramus and its medial and lateral branches that emanate from each spinal nerve. This network of nerves from the dorsal ramus contributes greatly to chronic discogenic and axial back pain not responsive to nonsurgical treatment. It is undetected by MRI or CT scan, but can be visualized endoscopically and confirmed by meticulous cadaver dissection (Figure 64-1B, C). Rational treatment calls for the appropriate and effective use of diagnostic and therapeutic diagnostic procedures such as diskography, selective nerve root blocks, foraminal epidural steroid blocks, facet and medial branch blocks, and sympathetic nerve blocks. Research studies, such as those by Caragee¹⁸, that emphasize the risks and the difficulty of interpretation of diagnostic tests such as diskography without balancing the indications and usefulness of the diskography, does a disfavor to endoscopic minimally invasive surgeons who are able to look at pathoanatomy and are skilled at spinal endoscopy. This skill affords endoscopic surgeons the opportunity to treat lumbar pain and sciatica without fusion.

The politics and social-economic pressures of medicine create even more controversy as poorly qualified “experts” provide personal opinion on “standard of care” in medical-legal and insurance coverage disputes.

The information obtained from these diagnostic and therapeutic injection procedures allows the surgeon to more selectively pinpoint the pain source and to determine how to mitigate the source of pain.

Indications and Contraindications

A widely accepted indication for foraminal endoscopic disc surgery is currently a foraminal or extraforaminal lumbar disc herniation. All sizes and types of herniations, however, are possible in the hands of a skilled and experienced endoscopic surgeon. Indications rely heavily on the skill and experience of the surgeon, as well as the patient’s anatomy relative to the location of the herniation and the ability to access the herniation. Indications may also depend on injection and imaging studies to identify a painful condition of the disc. The painful condition is currently identified by preoperative diagnostic and therapeutic injections such as evocative chromo-diskography, foraminal epidurography, therapeutic foraminal blocks, or selective nerve root blocks. Small disc herniations with sciatica, herniations with predominant back pain from the herniation, and annular tears that cause chemical sciatica that may be considered relative contraindications for traditional surgery because of the surgical risk-benefit ratio of the procedure, but may be an indication for foraminal endoscopic surgery. Any condition that obviously benefits from intradiscal therapy such as intradiscal debridement of diskitis is best performed percutaneous transforaminally. Contraindications are relative, dependent on percutaneous access to the pathoanatomy and the interventionalist’s experience. It is not unusual to find pathoanatomy, such as chronic granulation and inflammatory tissue in the disc or furcal nerves in the foramen, that is not apparent on preoperative imaging studies, but is clearly visualized endoscopically during foraminal endoscopic surgery.

Description of the Device

The design of the endoscope and endoscopic system is an important factor for endoscopic surgeons to consider. Techniques of endoscopic decompression vary depending on the endoscope design, the available surgical instruments, and surgical techniques practiced by the developer of the system. Not all endoscopic systems are designed for or amenable to the technique described here, but techniques and endoscopic systems continue to evolve. This chapter specifically describes the YESS transforaminal “inside-out-technique,” utilizing the YESS foraminoscope (Figure 64-2) and the instruments designed for the system and technique. Not only is it important to have the necessary instruments, but specially configured cannulas are designed to expose the pathoanatomy to be surgically treated but, in the process, also protect vital anatomy such as the nerve and dura. Other systems are also evolving, so that in time, there will be similarities evolved and copied from the YESS transforaminal technique illustrated here.

FIGURE 64-2 Richard Wolf YESS Multichannel Operative Endoscope. The spinal endoscope is designed with an operative channel, multichannel irrigation for improved visualization, and a cannula system configured to enhance surgical access to pathoanatomy while protecting sensitive anatomy such as spinal nerves.

(Reprinted from Yeung CA, Hayes VM, Siddiqi FN, Yeung AT. Lumbar endoscopic posterolateral (transforaminal) approach. In Motion preservation surgery of the spine. Yue JJ, Bertagnoli R, McAfee PC, An HS (eds). Philadelphia, Saunders/Elsevier, 2008.)

Background of Scientific Testing and Clinical Outcomes

Peer-reviewed literature for disc herniation, first reported by Mayer and Brock¹⁹ in 1993³ then by Hermantin² in a prospective randomized study, has concluded that the results with transforaminal endoscopic (coined “arthroscopic” by Kambin²⁰) diskectomy in the lumbar spine are generally similar to those with open diskectomy, but with significantly less surgical morbidity and quicker recovery (Table 64-1). The YESS technique evolved from the original Kambin technique as Yeung originally learned from Kambin. The procedure, done on an outpatient basis, utilizes local anesthesia with sedation. Patients are usually discharged an hour after surgery. Results show that patients use less postoperative pain medication and return to work within 1 to 6 weeks. It is not unusual for individual patients to return to work in a matter of days. Long-term follow-up has demonstrated decreased recurrence (6%), less postlaminectomy syndrome, and greater patient satisfaction overall. Morganstern, a student of Yeung²¹, has reported⁶ that after a learning curve of approximately 70 patients utilizing the YESS technique for a wide spectrum of disc herniation types, a 90% overall good/excellent result by MacNab and modified MacNab criteria is achievable. The 90% standard was the goal established for endoscopic surgeons wishing to take up the procedure. The results for all types of herniated nucleus pulposus (HNP), through 2008, as reported in the literature are summarized in Table 64-2.

TABLE 64-1 Microdiskectomy versus Endoscopic Diskectomy^∗

∗ Sixty patients randomized, 30 per group.

From F.U. Hermantin,T. Peters, L. Quartararo, et al. A prospective randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. Journal of Bone and Joint Surgery 81A ( 1999 ) 958 – 965.

The YESS endoscopic transforaminal approach, described in this chapter, also addresses a wide spectrum of painful degenerative conditions of the lumbar spine. The results of highly selected patients for these painful conditions have been reported at national and international spine meetings, but the clinical results of endoscopic treatment contained and noncontained HNP studies were last reported in 2004. Over 3,000 cases recorded on an excel database ranging from 1- to 10-year follow-up using clinical standardized measurements such as visual analog scale (VAS), Oswestry Disability Index (ODI), SF 12 (lifestyle disability scale), and MacNab criteria are currently being collated independently for peer-reviewed publication.

The endoscopic foraminal approach, differentiated from the posterior approach, emphasizes the dilation along tissue planes without damage to normal anatomy. The foraminal approach for disc herniation utilizing the “inside-out-technique” provides easy access for central, paracentral, and subligamentous foraminal and extraforaminal disc herniations through natural tissue planes between the longissimus and psoas muscles (Figure 64-3). For foraminal and large paracentral herniations, it is easy to visualize the lateral edge of the traversing nerve (Figure 64-4) once the herniation is removed. If the fragment is large and extruded, it comes out as an intact collagenized fragment. Prodromal symptoms of disc herniation in the aging spine usually arise from annular tears, which cause recurrent back pain and sciatica before the disc herniates. The opportunity to study and treat painful annular tears endoscopically that do not heal naturally provides information on validating the theory of electrothermal therapy but also sheds light on the reasons why the usefulness of blind radiographic methods will always be limited. Identification of granulation tissue and nucleus material in the annular layers (Figure 64-5A) provides a good prognosis for those tears treated with thermal annuloplasty. The nucleus material that weakens the annulus must be removed before the annulus is cauterized to close the tear. Using a biportal approach and a 70-degree scope, cauterization and confirmation of successful thermal annuloplasty under direct endoscopic visualization provide confirmation that the tear is closed and sealed (Figure 64-5B).

FIGURE 64-3 Basic “Inside-Out-Technique” for Endoscopic Disc Decompression. Uniportal technique for selective endoscopic diskectomy. After introduction of a beveled cannula, endoscopic microrongeurs are used for visualized fragmentectomy. This is followed by use of specialized hinged rongeurs and straight and flexible shavers to remove the soft nucleus from the annular herniation defect.

(Reprinted from Yeung CA, Hayes VM, Siddiqi FN, Yeung AT. Lumbar endoscopic posterolateral (transforaminal) approach. In Motion preservation surgery of the spine. Yue JJ, Bertagnoli R, McAfee PC, An HS (eds). Philadelphia, Saunders/Elsevier, 2008.)

FIGURE 64-4 Traversing Nerve after Removal of a Extruded Foraminal HNP. Indigo carmine dye stains the degenerative nucleus blue, helping the surgeon to selectively remove not only the extruded, sequestered disc herniation, but also the loose degenerative disc material, which could become the source of a recurrent herniation. Here, the decompressed traversing nerve is clearly visualized to confirm complete decompression of the herniation. Intraoperative or postoperative CT scan or MRI is not needed to confirm complete decompression of the spinal nerve when visual confirmation confirms successful removal of the herniation. The real-time extraction of the herniation fragment, followed by direct visualization of the decompressed nerve, confirmed by the conscious patient providing immediate feedback reporting immediate relief of leg pain, precludes the need for traditional evidence based medicine calling for a double-blind, randomized study to validate the selective endoscopic diskectomy technique or any visualized endoscopic technique designed to address the pathoanatomy.

FIGURE 64-5 Endoscopic Thermal Annuloplasty of Annular Tears. A, Painful annular tear identified endoscopically after intraoperative chromo-diskography confirms the presence of a grade IV annular tear with disc tissue embedded in the annular fibers. Tears that don’t heal have imbedded disc material preventing the tear from healing naturally. The nucleus material must be removed from the annular layers before the results of thermal annuloplasty is predictable. This is the reason the surgical results of IDET is not predictable. Selective endoscopic diskectomy removes degenerative disc material as well as the nucleus embedded in the annulus. Endoscopic thermal annuloplasty follows. Tears vary in size, location, and type. One or two quadrant posterior and posterolateral tears in patients with 20% to 25% remaining annular thickness have good long-term results following endoscopic thermal annuloplasty. More extensive tears will also heal, but can tear again. Painful annular tears are best diagnosed with Evocative Chromo-Discography and confirmed by endoscopic visualization of the tear. Diskography performed by the surgeon evokes the pain, while the indigo carmine dye helps locate the tear. Granulation and inflammatory tissue are often found adjacent to the tear, and visual documentation of tear closure provides evidence of endoscopic thermal annuloplasty in the treatment of painful annular tears as a source of pain in the aging spine. B, Illustration of selective endoscopic diskectomy and thermal annuloplasty technique for a grade IV Tear. C, Grade III-IV annular tear cauterized and closed with bipolar radiofrequency thermal annuloplasty as viewed through a 70-degree scope. The prognosis for this tear is good because the tear is completely closed, and 20% to 24% of the annulus is still preserved after closing the tear.

The technique for endoscopic foraminoplasty in more advanced disc degeneration and foraminal narrowing is associated with central and foraminal stenosis, not only for lateral recess stenosis but also for foraminal decompression of the ventral facet in tall discs to gain “inside-out” access to sequestered herniations in the epidural space. A foraminoplasty cannula exposes the ventral aspect of the superior facet for endoscopic decompression (Figure 64-6A), which helps strip the capsule and define the undersurface of the facet to be removed with trephines and burrs (Figure 64-6B). Degenerative spondylolisthesis is often associated with disc protrusions and lateral stenosis, whereas sciatica from isthmic spondylolisthesis, due to the mechanical compression of the axilla and subarticular recess (Figure 64-6C), is effectively treated by endoscopic foraminal decompression in selected patients. These patients usually improve temporarily with foraminal diagnostic and therapeutic injections. Endoscopic decompression of the foramen can provide enough relief that the patient will avoid fusion. Failed back surgery syndrome (FBSS) patients with lateral recess stenosis and recurrent disc herniation also respond well. When the support is shifted posteriorly to the facet joints, synovitis and facet cysts may form. These cysts may impinge on the spinal nerves. Pedunculated cysts are sometimes visualized endoscopically, especially if the cyst wall is stained by indigo carmine or is visualized in the course of a diskectomy for chronic sciatica (Figure 64-7). Degenerative and isthmic spondylolisthesis (Figure 64-8A-D) can also be treated endoscopically with proper interventional injection workup. Impingement from the disc or superior facet of the inferior vertebra can be sorted out with diagnostic and therapeutic injections. If evocative diskography evokes concordant back pain and/or sciatica, and foraminal epiduralgrams and therapeutic injections provide information of the pathoanatomy, then careful preoperative planning will provide information on the likely outcome of foraminal decompression.

FIGURE 64-6 A, Endoscopic foraminal decompression. In more advanced aging, foraminal stenosis and osteophytosis can cause impingement of the spinal nerves. A specially configured cannula is placed under the facet for foraminal decompression. A side-firing laser is useful to strip the capsule from the facet; then a trephine and high-speed diamond burr are used to decompress the ventral portion of the facet to enlarge the foramen and elevate the foraminal window to gain access to the epidural space. The exiting nerve is then followed into the epidural space to decompress the axilla between the traversing and the exiting nerve. Decompression continues until the lateral edge of the traversing nerve is visualized or until fat is seen in the foramen. B, Foraminal decompression may be performed in conjunction with disc decompression or as a stand-alone procedure. Here, the illustration demonstrates the use of the holmium:yttrium-aluminum-garnet side-firing laser to strip the capsule from the ventral facet. More extensive decompression may be further performed with trephines, endoscopic Kerrison rongeurs, high-speed endoscopic burrs, or rasps. C, Decompressed exiting nerve for lateral recess stenosis. A high-speed diamond burr was used to complete the superior facet decompression to free the exiting nerve by stripping the facet capsule and removing 4 mm from the ventral surface of superior facet.

FIGURE 64-7 Pedunculated Synovial Cysts. Pedunculated cysts may be difficult to see on MRI because they may vary in size and are sometimes seen incidentally during foraminal surgery. It does not have to be located adjacent to the facet joint, because the cyst may be medial or lateral to the joint. Here the cyst, accompanied by a plexus of blood vessels, is found in the foramen compressing the exiting nerve. Usually a cyst is suspected from the finding of a bright signal adjacent to the facet capsule.

FIGURE 64-8 Both isthmic and degenerative forms of spondylolisthesis are treatable endoscopically if the pain generator can be demonstrated to come from the disc or foramen. A, Lateral MRI demonstrates a degenerative spondylolisthesis with a disc protrusion contributing to central stenosis. The disc can be decompressed endoscopically, but the risk of instability with further slippage is increased. B, There is foraminal stenosis causing sciatica. This patient had right sciatica, not left; good relief was obtained with a foraminal epidural block on the right. C, Endoscopic foraminoplasty identified impingement of the exiting nerve by the tip of the superior facet of the inferior vertebra. D, A furcal nerve was found in the foramen, possibly also contributing to the patient’s sciatica. His sciatica resolved following foraminal endoscopic decompression.

Clinical Presentation and Evaluation

The clinical presentation and evaluation for endoscopic decompression are the same as for the techniques used for traditional transcanal surgery. FBSS patients, however, represent a large and diverse group of spine surgery patients who have previously undergone spine surgery to treat back pain, yet they continue to suffer from back pain and sciatica after one or more spine surgeries. FBSS can be the result of an initial failure to recognize all of the pain generators, failure of the initial surgery (inadequate disc removal), recurrence of the original pathology (recurrent disc herniation), or progression of the underlying condition (lumbar spondylosis and facet arthrosis). The endoscopic applications outlined in this chapter are applicable to all of these conditions and often obviate the need for large instrumented fusions or implants such as spinal cord stimulators. Preoperative evaluation incorporates correlation of the findings on imaging studies such as MRI, CT scan, diskography, and CT/diskography.

Operative Technique(s)

Postoperative Care

A postoperative lumbar corset will make the patient feel more comfortable. Before removal of the access cannula, routine use of depomedrol 80 mg delivered with 0.5% bupivacaine (Marcaine) (1-2 ml) will provide immediate postoperative analgesia; there have been no instances of infection from the use of steroids. The patient should be instructed to avoid bending, lifting, and twisting for 4 to 6 weeks to allow the annulus to heal and to reduce the incidence of recurrent disc herniation from the foraminal access portal and from an annular defect produced by the disc herniation. Physical therapy is not required but can be considered on an individual basis. Patients are instructed to use their pain as a guide to activity after the 6-week period.

Complications and Avoidance

The risk of serious complications or injury is low—approximately 1% or less in the authors’ experience. As with any surgery, there are the usual risks of infection, nerve injury, dural tears, bleeding, and scar tissue formation. Transient dysesthesia, the most common postoperative complaint, occurs in approximately 5% to 15% of cases and is almost always transient. Its cause remains incompletely understood, but a detailed study of foraminal anatomy reveals an extensive network of nerves that can be surgically irritated, even with the most careful use of surgical instruments. Dysesthesia may also be related to nerve recovery, operating adjacent to the dorsal root ganglion of the exiting nerve, or a small hematoma adjacent to the ganglion of the exiting nerve, because it can occur days or even weeks after surgery. There are also anomalous nerve fibers in the annular tissue, which may be furcal nerves or

nerves growing into an inflammatory membrane in the area of the foramen that is not the traversing or exiting nerve. It could show up in the surgical specimen without permanent effect on the patient, but may cause temporary dysesthesia. Using blunt techniques to dilate the annular fibers has limited surgical morbidity and the excisional biopsy of tissues (anomalous nerves) caused by neo-neurogenesis and angiogenesis from the surgical specimen, but dysesthesia cannot be avoided completely, because it has occurred even when there were no adverse intraoperative events and in cases in which the continuous electromyography (EMG) and somatosensory evoked potentials (SEP) did not show any nerve irritation. The symptoms are sometimes so minimal that most endoscopic surgeons do not report it as a “complication.” The more severe dysesthetic symptoms are similar to a variant of complex regional pain syndrome, but usually less severe, and without the skin changes. Postoperative dysesthesia is treated with transforaminal epidurals, sympathetic blocks, and the off-label use of pregabalin 150 mg/day or gabapentin titrated to as much as 1800 to 3200 mg/day. Gabapentin is approved by the U.S. Food and Drug Administration (FDA) for postherpetic neuralgia, but is effective in the treatment of neuropathic pain. The close proximity of sympathetic nerves and their role in disc innervation is still poorly understood, but treatment of dysesthesia by blocking the sympathetic trunk has produced dramatic results, especially when provided early in the course of postoperative dysesthesia.

Avoidance of complications is enhanced by the ability to visualize normal and pathoanatomy clearly, as well as through the use of local anesthesia and conscious sedation rather than general or spinal anesthesia. Adopting the “inside-out-technique” will give the surgeon more leeway in planning the surgical approach, since direct targeting to the herniation based on imaging studies may provide some “surprises” when visualization is not as clear as anticipated because of bleeding, and the herniation turns out to be more than a simple herniation not appreciated by the imaging study. Staying inside the disc space or returning to the disc space when visualization is obscured to reorient the surgeon is an important factor to consider. In experienced hands, some surgeons have safely utilized general anesthesia when circumstances make it safer for the patient. With use of a local anesthetic, the patient usually remains comfortable during the entire procedure, with the exception of periods such as during Evocative Chromo-Discography annular fenestration, or when instruments are manipulated past the exiting nerve. Local anesthesia of 0.50% lidocaine permits generous use of this diluted anesthetic for pain control but allows the patient to feel pain when the nerve root is manipulated. Nerves can also be adherent to the annulus or nucleus. Pain experienced by the patient is very helpful to the surgeon when probing or operating in the foramen, as it permits documentation or release of these adhesions before removing the herniation.

Conclusions and Discussion

In summary, endoscopic posterolateral lumbar diskectomy and foraminal decompression provides a visualized method for minimal access to the disc and epidural space that avoids surgical morbidity to the dorsal muscle column. This endoscopic approach also allows for the visualization of foraminal and intradiscal pathology that is not appreciated by the traditional approach. Inflammation pays a major role in pain production. The correlation of these conditions and findings with pain generation may open the door to a better understanding of the degenerative process causing lumbar disc herniations, and our concept of surgical intervention that encourages patient selection for earlier intervention may evolve as well. Following foraminal diskectomy and decompression, the traversing nerve, exiting nerve, axilla, and epidural space are all able to be probed and visualized. It is not always necessary to directly visualize all structures if there is good indirect evidence that the painful structure is being appropriately addressed; an example is decompression of a central disc herniation by visualizing the annulus and annular tears with an intradiscal view of the annulus. Patients can also provide confirmation that their leg pain is gone when undergoing surgery under conscious sedation. A closer study of posterior column and facet innervation will also open the door for endoscopic nerve ablation techniques that can be used for axial back pain.

In this area of health care reform, identifying the pain generator early, and treating it with a minimally invasive technique with surgical pain management, may lead to cost savings by decreasing our dependence on drug usage for chronic pain, and large expensive destructive surgery spine surgery such as fusion. Any technology to help surgeons attain proficiency through surgical training simulators or improved imaging capability, preoperatively or intraoperatively, should be part of the equation in health care reform.