The CMEDF approach in indicated in the following cervical pathologies and situations [42–44]:

The following surgical equipment and instruments are necessary to perform CMEDF:

The CMEDF procedure is performed under general anesthesia with orotracheal intubation. Occasionally the procedure can be performed under local anesthesia in younger patients. Preoperative antibiotics are admitted and dexamethasone might be administered to minimize airway and esophageal edema. The patient is positioned supine with the neck slightly extended. The head might be rigidly affixed via pins in a Mayfield holder. The shoulders are gently tapped down to enhance visualization of the lower cervical spine with intraoperative lateral fluoroscopy. The segment(s) to be operated on can be identified by intraoperative C-arm fluoroscopy. In case of a two- or three-level procedure, a small (18–20 mm) transverse skin incision is recommended to be place at the midpoint of the operative distance. The prevertebral anatomical structures have the characteristics to be movable. Skin incision has to be made deep to the platysma before subplatysmal structures can be dissected by index and the middle finger. The larynx is pushed toward the opposite side with the index and middle fingers while muscle and the carotid was held laterally. Next fingers were slipped inside towards the front of the vertebral body until the anterior cervical spine and edge of the disc is palpated. Optional an artery forceps is placed through the skin incision between both fingers with its blunt tip kept at the vertebral leading edge by creating an access path. Next step the endoscopic tubular dilators were introduced sequentially under fluoroscopic guidance between the carotid artery and the esophagus. A working trocar with an outer diameter of about 18–20 mm is introduced at last and fixed to a mechanical flexible holding arm which is attached to the operating table. After confirming the correct level via lateral C-arm-fluoroscopy the dilators are removed and endoscope system of choice is installed. The anulus fibrosus of the disc is incised by using a microknife before the nucleus pulposus is removed. Osteopytes can be removed by Kerisson punch or diamond drill. Continuous irrigation with saline solution is recommended to remove remaining fragment and to prevent thermal nerve damage in case of drilling. An arterial or any kind of source of bleeding from paraspinal muscular can be controlled by bipolare forceps. Micrograsper, microforcep, dissectors and small curettes are used to remove the rudiment of the disc of the vertebral body. Special curettes are available to dissect the remnant cartilage endplates and enlarge the intervertebral space. Since distraction screws are not placed manual cervical distraction is performed to widen the interbody space by pushing up the head gently and pulling down the arms at the same time. Another technique for distraction is placing a 5 mm osteotome in the disc followed by its twisting. A cage of choice is placed under fluoroscopic guidance and optional filled with bone graft substitutes. After removal of the tubular retractor, the subcutaneous tissue is closed in standard fashion with a skin adhesive and steristrips the placement of a suctions drain is optional (Fig. 7.2).

The APECD approach in indicated in the following cervical pathologies and situations [41, 53–55]:

The following surgical equipment and instruments are necessary to perform APECD [40, 41, 55]:

The patient can be operated on under local anesthesia with light sedation so the surgeon can talk to the patient and be aware of any neurological changes. However, if preoperatively there is a sign that the patient may suffer from intraoperative psychological or physical stress because of the introduction of the endoscopic system, general anesthesia can be used as an alternative instead. Preoperative antibiotics are admitted and dexamethasone might be administered to minimize airway and esophageal edema. The patient is placed in a supine position with the neck mildly extended on a radiolucent table. Intraoperatively fluoroscopic guidance (C-arm) the segment of operation is carefully identified in lateral and a.p. X-ray using a radiopaque instrument. Skin incision is marked and with a felt-tipped pen and the skin and subcutaneous tissue were infiltrated with local anesthetic (e.g. 1 % xylocaine, 1 % lidocaine). Generally the approach is at the contralateral side about 2–5 mm paramedian from the midline. The anatomical structures are very mobile due to the compartmentalization and ideal for an anterior percutaneous approach. The goa is to displace the trachea and esophagal medially and the carotid artery and internal jugular vein laterally. First the pulsation of the carotid artery should be felt, then the visceral structures (thyroid, trachea, larynx, and esophageal) can be mobilized to the opposite side with the index finger. The middle finger is then slipped inside towards the cervical spine till the protruding ring of the disc is felt between both plane forefronts of the vertebral bodies. Under continuous fluoroscopy a 18-gauge puncture needle is then carefully inserted in the space between the visceral and vascular compartment into the disc space close to the posterior body line of the posterior part of the disc, trying to preserve the longuscoli muscle. A next step of the surgery a discography (e.g. 10 mL Telebrix and about 0.5 mL of contrast media e.g. indigo carmine is injected to specify the posterior part of the disc) is performed to determine the annular tear, to confirm the presence of soft disc herniation, and to stain the nucleus pulposus into blue in contrast with the neural tissue. Then a guide wire is inserted to replace the puncture needle and is skin incision of 3 mm is made to allow the dilation of the skin and soft tissue via serial progressive dilator (2–5 mm). By this technique soft tissue is prevent from trauma and the approach-related pain is reduced. Finally, the tip of the working cannula is firmly placed to reach the posterior part of the disc. Its correct position sis confirmed via fluoroscopy. The distance between the tip of the working cannula and the end of the posterior longitudinal ligament represent the working depth for the endoscopic instruments. Next the endoscope is inserted into the working cannula. Continuous saline mixed with antibiotics (e.g. cefazolin) is used as irrigation. First endoscopic images of the intradiscal cavity are visible on a monitor. Under endoscopic visualization the herniated disc fragments are removed with microforcep and trephine without injuring the spinal cord. The risk of instability or local kyphosis may be avoided by leaving the anterior fraction of the disc intact while removing the posterior aspect. If necessary the endplate and parts of the posterior edge of the vertebral body are ablated via a Holmium yttrium–aluminum–garnet

(Ho:YAG) laser. Further the laser can be used to shrink the remaining disc herniation and to vaporize abnormal annular structures. A low doses of energy for laser with 2 J and 10 Hz is recommended, therefore YAG-laser is about 0.3–0.5 mm deep. The laser may be useful to create intradiscal cavity for exploration of adequate decompression. At the end of decompression posterior longitudinal ligament or dura should be clearly visible. Discoplasty of the working cannula surrounding disc tissue may be performed by YAG-laser before removing the working cannula. Position of the laser should be frequently checked via endoscope and fluoroscopy to prevent spinal cord or nerve root injury. Further an expandable holder or autologous iliac bone graft can be introduced for stabilization. The initial diameter of the holder is 3.3 mm while its inserted into the intradiscal cavity. It can be expanded up to 7.0 mm in diameter inside the disc by rotating the expander rotational handle. It is then fixed to the disc. The correct position is controlled under fluoroscopic guidance. If the procedure is performed under local anesthesia the surgeon can interact with the patient and ask whether the preoperative pain has disappeared or was relieved during surgery. The endoscope and working cannula were carefully pulled out. The remaining irrigation and blood is drained before the wound is closed in standard fashion (Fig. 7.3).

The EPCLF approach in indicated in the following cervical pathologies and situation: