Contemporary Endoscopic Spine Surgery

Endoscopy of the cervical spine traditionally has been slow to adopt. Initially, spinal endoscopy concentrated on common painful degenerative conditions of the lumbar spine, for which many of the technology breakthroughs were developed. Many of them were validated for defined clinical indications, such as a herniated disc. Stenosis applications followed later as improvements in the endoscopic platform permitted. Cervical spine application of endoscopic surgery commenced around interventional pain management with lasers and radiofrequency to improve their reliability by directly visualizing the painful pathology. Later, anterior cervical discectomies and posterior cervical foraminotomies were performed as endoscopic power burrs, and rongeurs made them possible. The most skilled surgeons moved on to perform anterior and posterior cervical spinal cord decompressions and anterior column reconstructions endoscopically further to take advantage of the potential of this platform so they could transform the traditional surgical treatments from inpatient to outpatient by performing them in a simplified manner in ambulatory surgery centers where better clinical outcomes and higher patient satisfaction could be achieved. In this chapter, the authors strove to briefly illustrate this development by giving credit to the most prominent pioneers of this fast-moving field and by setting the stage for what the reader is about to discover in this most-up-to date publication entitled: Contemporary Spinal Endoscopy: Cervical Spine.

Anesthesia for the outpatient ambulatory surgery center has to be tailored to the surgery. The length of surgery, the trauma of painful dissection, and the amount of blood loss have to be considered. Outpatient spine surgery is characterized by shorter simplified versions of their inpatient counterparts carried out in a hospital setting. Many outpatient spine surgeries are minimally invasive through small incisions with less blood loss, tissue disruption, and, more importantly, less painful stimulus during surgery. These modern spine surgery versions also apply local anesthesia strategically to diminish the need for deep anesthesia. In some scenarios, the surgeon may wish to speak to the sedated yet awake patient to lower the risk of injury to neural structures when performing the more dangerous portions of the endoscopic decompression surgery. The need to communicate with the patient is undoubtedly of high relevance in the cervical spine, which requires the anesthesiologist to tailor the management of the patient’s anesthesia to the surgeons’ needs. The monitored anesthesia care (MAC), where sedation is achieved with various sedatives and narcotics, is most appropriate for outpatient endoscopic cervical spinal surgeries. These surgeries may be performed with the patient in supine (anterior cervical surgery) or in a prone position (posterior cervical surgery). Patients in the prone position may pose additional problems maintaining adequate ventilation and sedation while keeping the patient comfortable enough to tolerate the procedure and yet still communicating with the surgeon. In other scenarios or different surgeon preferences communicating with the patient during an outpatient endoscopic cervical surgery may not be required. A Laryngeal Mask Airway (LMA) may be more appropriate with the patient in a prone position. This chapter describes modern MAC concepts, airway management in the supine and prone position, and sedatives as it applies to cervical endoscopic spinal surgery in an ambulatory surgery center.

Full endoscopic surgery of the cervical spine has gained more popularity, raising the question of its indications, patient selection criteria, and the appropriate choice of the various anterior and posterior techniques. In this chapter, the authors attempt to delineate the criteria for selecting patients for the different full endoscopic surgical techniques for the cervical spine's common painful degenerative conditions. The authors review the common forms of surgical pathology, including foraminal, lateral- and central canal stenosis, and distinguish between radiculopathy and myelopathy. They introduce algorithms for the full endoscopic treatment of these conditions by relying on validated classification systems for cervical disc herniations and their associated appearance on advanced imaging studies, including magnetic resonance imaging and computed tomography. Moreover, the authors review the risks, contraindications, and limitations of the various anterior and posterior full endoscopic surgery techniques related to the current technology standards.

Full endoscopic surgery of the cervical spine is done in select centers where the clinical and surgical expertise is high. The procedure can be potentially dangerous in less well-trained hands, with the prospect of damage to vital vascular structures, and injury to the trachea, esophagus, cervical nerve roots, and the spinal cord. Also, cervical endoscopy is competing with traditional spinal surgeries, such as anterior cervical discectomy and fusion, or posterior cervical foraminotomy, whose clinical outcomes are reliably favorable. Therefore, most surgeons have a hard time replacing their well-performing anterior- or posterior cervical surgeries that they may very well be carrying out through open or mini-open incision or other forms of minimally invasive spinal surgery techniques. Patient satisfaction with these procedures is generally very high, and the complication rate is relatively low, and their management is well-understood. Again, is there a need for change? It is apparent that to the innovators, the answer to this question is obviously “yes” because they are looking for practical, yet less burdensome, lower cost, and more simplified outpatient cervical spine surgeries. The general push by payors and patients to transition spine care from in- to outpatient setting requires spine surgeons to rethink their approach to treating common degenerative conditions of the cervical spine. New algorithms based on updated classification systems and clinical outcome analysis of contemporary surgical techniques are required to make this transition feasible. In this chapter, the authors illustrate the application of full-endoscopic cervical spine surgery techniques, reviewing their indications, and the clinical decision-making by discussing the rationale for the procedure of choice selection ranging from patient criteria, anatomical considerations, surgeon training-, and skill level. This chapter is intended to serve as a guide for the established spine surgeons who are yet inexperienced with endoscopy and evaluates whether full endoscopy of the cervical spine should be in their armamentarium.

Axial neck pain without much radicular shoulder arm pain is a somewhat tricky situation for spine care providers. Patients often have the early-stage degenerative disease of the cervical intervertebral disc and facet joints, with minimal spinal alignment changes and without instability. Yet such patients may have legitimate symptoms and may have failed multiple rounds of physical therapy, spinal injections, activity modifications, non-steroidal anti-inflammatories, and other medical and supportive care measures. These patients may not fit traditional image-based spinal care protocols and are mostly left untreated. This chapter presents the authors' indications, and clinical outcomes with an endoscopically visualized combined mechanical and radiofrequency facet ablation with a minimal laminotomy at the symptomatic levels. They offer their rationale behind their strategies to attend to these patients with minimal cervical spine disease on advanced images but with unmanageable complaints who ordinarily have been falling into this watershed area of traditional spine care and reviewing possible pain relief mechanisms. The latter may be achieved not only by the combined mechanical and radiofrequency ablation of the cervical facet joint complex but also rely on modulation of the activity of the dorsal root ganglion of the cervical nerve root at the affected level. Outcomes are favorable in most patients, suggesting the authors' approach to treating these patients has merits; thus, warranting further clinical validation.

Anterior endoscopic cervical discectomy (AECD) is a surgical procedure born in the era of minimally invasive spine surgery. A cervical discectomy through a 4 mm incision, in skilled hands, can be an ambulatory outpatient procedure where the patient may be discharged the same day from the surgical facility. Recent advances in video-endoscopic equipment and decompression tools have facilitated endoscopic spinal surgery techniques to common soft disc herniations in the cervical spine. The authors review the procedural steps of the procedure and position it as a motion preservation surgery that may alleviate radicular symptoms in the upper extremities that have not responded to non-operative care. Unrelenting arm pain in the younger patient with early degeneration of the cervical spine motion segments may be the most appropriate indication for the AECD. Procedural details and outcomes from a clinical series are reviewed to illustrate technical pearls and postoperative problems common to the procedure – with segmental kyphosis and vertical collapse of the disc space being the most relevant – if not carried out with attention to detail.

Percutaneous endoscopic cervical discectomy (PECD) was designed to bridge the gap between failed medical- and interventional care for cervical radiculopathy due to small herniated discs and traditional open anterior cervical discectomy surgery many of which employ fusion and far fewer motion preservation strategies. PECD can be divided into the anterior transdiscal- and the posterior interlaminar approach. Anterior PECD has been criticized for the potential propagation of cervical disc collapse due to the more aggressive disruption of the anterior annulus. Additional limitations of the anterior transdiscal PECD may become relevant when upward or downward disc fragments are entrapped behind the vertebral body. Even during ACDF, a corpectomy may be required to remove these far-migrated disc fragments. Therefore, the authors advocated for the anterior transcorporeal approach through a small bony channel through a cervical vertebral body. The surgical trajectory can be freely aimed at the compressed pathology giving the surgeon more flexibility to remove the herniated disc while preserving the motion of the surgical- and possibly adjacent segments by limiting the bony resection required to gain access to the disc herniation. The authors present case examples to illustrate the involved surgical steps, required equipment, discuss pitfalls, and technical details to achieve reliable clinical improvements without complications. This simplified anterior cervical decompression procedure improved their patients without surgery-related complications, such as dysphagia, Horner’s syndrome, recurrent laryngeal nerve palsy, vagal nerve injury, tracheoesophageal injury, or anterior cervical hematoma. The authors concluded that the transcorporeal PECD is suitable for the outpatient setting in an ambulatory surgery center, provides excellent direct visualization of the herniated disc with little iatrogenic injury to the cervical spine. Thus, it minimizes the risk of secondary decline of intervertebral height due to access-induced advanced cervical disc degeneration commonly seen with anterior transdiscal approaches.

Cervical foraminotomy is a popular procedure with surgeons to treat patients with refractory cervical radicular pain. Traditionally, it has been performed from the posterior approach. With the advent of minimally invasive spinal surgery techniques (MISST), anterior methods have also been employed to approach the compressive pathology from the axilla of the painful cervical nerve root. The authors of this chapter present their technique of transdiscal endoscopic anterior cervical discectomy foraminoplasty using an instrument system comprised of serial dilators, trephines, rongeurs, and a pulsed radiofrequency probe. They demonstrate the steps of the procedure from patient positioning, placement of surgical access, the employment of the individual surgical instruments, and their clinical outcomes. The authors briefly describe their clinical experience over a twenty-one year period. They performed a total of 232 procedures on 169 patients with single and up to 4 level surgeries herniate disc (219/232; 94.39%). An additional 13 patients (4.9%) had procedures for the treatment of lateral cervical canal stenosis. At a one-year follow-up, 90% of patients were rated to have had Excellent and Good Macnab outcomes, whereas Fair and Poor results were reported by 7%, and 3% of patients, respectively. In the absence of intraoperative or postoperative complications or reoperations associated with the procedure, the authors recommended it as a simplified outpatient alternative to anterior cervical discectomy and fusion.

Cervical radiculopathy is a common disabling condition resulting from advanced degeneration of the cervical spine. Posterior Endoscopic Cervical Discectomy (PECD) surgery preserves soft tissue and accomplishes a form of foraminal decompression with a lower propensity to postoperative instability. The authors described the technique in detail with an illustrative case example and intraoperative endoscopic images. The targeting point is the “V” point made up by the lateral margin of interlaminar space and medial border of facet joint junction. This confluence of the medial junction of the superior and inferior facet can easily be recognized on AP view where it has the appearance of a V. Furthermore; the authors present the results of a prospective clinical PECD study of 29 levels in 25 patients where they analyzed the radiological and clinical outcome with the trans v point PECD technique. Most of the PECD surgeries were carried out at the C5/6 and C6/7 levels. The mean follow up was 29.6 months. There was a 4% complication rate because of motor deficits, which had been resolved after one year. The majority of patients showed significant improvements in VAS and ODI scores, and 96% achieved good and excellent results by Macnab’s criteria. Retrospective evaluation of the radiological and CT data showed sagittal foraminal area increase and craniocaudal foraminal length increases. PECD produced the largest foraminal length increase preferentially in the ventrodorsal direction. Based on our observations, PECD is a good option in the posterior foraminotomy of the cervical spine. Clinical and radiological outcomes are favorable.

The authors describe the technique and clinical outcomes with the posterior endoscopic cervical spinal cord compression to treat cervical spondylotic myelopathy. A total of twenty-two cervical spondylotic myelopathy patients were treated with endoscopic spine surgery fusion from January 2015 to June 2017 at the Medical School of Chinese PLA. The operation time, intraoperative blood loss, and hospitalization stay were recorded and compared. Japanese Orthopaedic Association (JOA) scores before the operation, three months, and one year after operation were recorded and analyzed. There were twenty-two cases in the spinal endoscopy group. There were significant differences in preoperative JOA scores three months after surgery and one year after surgery. The JOA scores were significantly increased after surgery, and the symptoms gradually improved postoperatively. Clinical outcomes were Excellent in 81.8% of patients. The efficacy and safety of endoscopic spinal surgery for single-level cervical spondylotic myelopathy were established. The operation time, the intraoperative blood loss, and the hospitalization stay were reduced compared to historical numbers for competing decompression and fusion procedures.

The challenges of decompression surgeries performed in the cervical spine for degenerative spinal disease are 1) the avoidance of injuries to vital structures, 2) prevention of neurological deterioration, or deficit 3) preservation of cervical segmental stability to avoid post-decompression kyphosis 4) adequate decompression of neural structures. Endoscopic spine surgery optimizes two essential aspects of minimally invasive spine surgery: optimal visualization and minimal soft tissue damage. Despite using a small diameter endoscope, the proximity of exiting nerve root, spinal cord, and pedicle to the intervertebral disc make posterior endoscopic cervical foraminotomy and discectomy difficult. To remove the disc without significant neural retraction, our technique of full endoscopic partial pediculotomy, partial vertebrotomy posterior endoscopic cervical foraminotomy and discectomy (PECFD) allows the creation of a subneural working space for the endoscopic equipment to reach the prolapsed disc or hypertrophic uncovertebral joint. This chapter describes this technique and its clinical pearls to perform PPPV PECFD safely and efficiently.

Isolated discogenic cervical pain syndromes are somewhat difficult to treat. Many of these patients have underlying painful degenerative conditions of the cervical spine that do not meet accepted criteria for surgical treatments. Hence, many of these patients remain untreated or undergo interventional pain management procedures to meliorate the pain. The author presents a simple endoscopic outpatient method intended to treat a small subsection of this patient population complaining of isolated neck pain without any arm pain. Often these patients have end-stage degenerative cervical disc disease with near complete collapse with minimal associated foraminal stenosis. The author presents an endoscopic interbody fusion technique he has developed for these types for patients using an autograft bone dowel harvested from the iliac crest.

The authors describe the percutaneous endoscopic release of jumped and locked cervical facet joints under direct visualization as an alternative technique to open posterior decompression and reduction under capital traction. Instead of under general anesthesia, the procedure can be done under local anesthesia allowing the surgeon to communicate verbally with the injured patient while directly visualizing the decompression, release, and spontaneous reduction of the locked facet, thus, lowering the risk of unrecognized grave neurological complications. The author's endoscopic technique affords the surgeon the ability to provide the patient with a more simplified solution to the jumped and locked facet problem, thereby decreasing the overall morbidity and surgical risks associated with a combined anterior and posterior approach typically performed for this condition. The authors present a representative case example to illustrate their technique.

The authors present a case of cervical myelopathy due to degenerative stenosis of the spinal canal. They employed an endoscope to aid in the improved visualization during the release of ligamentous attachments between the cervical dural sac and the ventral aspect of the cervical lamina during laminoplasty. The patient had two paraspinal 2 cm incisions through which a MED tubular retractor was placed, and most of the bony decompression was done using an operating microscope. The lamina was detached from the lateral masses with a high-speed drill. The bony cuts in this lateral groove were completed with Kerrison rongeurs. Silk stitches were passed through the spinous processes to elevate the cervical laminae from the dural sac and create the posterior expansion of the cord's space. This bilateral laminoplasty was then secured with mini-titanium plates. The authors present their utilization of the spinal endoscope in improved visualization of the surgical dissection, which can be problematic even with an operating microscope through the small exposure afforded by the MED tubular retractor system. The illumination and magnification helped safely execute this hybrid operation that employed two different minimally invasive spinal surgery technologies, including the operating microscope and a spinal endoscope. In the authors' opinion, such hybridizations may be the stepping stone towards nextgeneration advances in the cervical spine's minimally invasive surgery.

The authors present a small case series to demonstrate the feasibility of employing the percutaneous approach to treating cervical spine tuberculosis. They placed a puncture needle under CT-guidance into the abscess to drain and debride preand paravertebral and retropharyngeal abscesses with endoscopically assisted technique. A pigtail catheter was placed into the abscess cavity for continuous intralesional delivery of antituberculous chemotherapy. Clinical outcomes were favorable. None of the three patients in this case series report experienced neurological function deterioration or needed more aggressive follow-up surgery. In this chapter, the authors set out to demonstrate the utility of the spinal endoscope in other areas of application distinct from decompression commonly required in degenerative spine disease.

Sequelae and complications following endoscopic surgery of the cervical spine are rare. They may range from neuropraxia, temporary and self-limiting loss of sensation, motor strength, loss of the voice due to recurrent laryngeal nerve injury, vascular and dural leaks to full-blown spinal cord injury with tetraplegia in the worst cases. In this chapter, the authors systematically review the most concerning problems the endoscopic spine surgeon may run into and discuss their management in the context of the most up-to-date peer-reviewed literature. Surgeon training and high skill level are of the utmost importance in minimizing potentially grave outcomes from the cervical spine's endoscopic spine surgery.