Identify and regularly check the pulsation of the carotid artery level localization. The structures at risk during this approach have been listed above. A deleterious pitfall is the risk of unintentionally retracting the carotid artery medially instead of laterally. Therefore, the pulse of this artery must be palpated to ensure that the artery is indeed lateral. The overall risk of operative complications remains small but significant [72]. In 450 cases of anterior cervical discectomy, the rates of recurrent nerve palsy and Horner’s syndrome were 1.3% and 1.1%, respectively [9]. However, the true rate of nerve root injury based on laryngoscopy is substantially higher (24%) [34]. Apfelbaum suggested monitoring endotracheal tube (ET) cuff pressure and release of the pressure after retractor replacement or repositioning has been used, which enables the ET to be recentered within the larynx [4]. The natural history of a recurrent nerve lesion is benign [34]. Complete recovery of vocal cord function was documented in 26 (93%) of 28 patients who had undergone a thyroidectomy [46]. Dysphagia is a not uncommon problem after anterior cervi- cal spine surgery. Overall the incidence of dysphagia 2 years after anterior cervi- cal spine surgery was 13.6% based on the analysis of 348 cases [43]. Risk factors for long-term dysphagia after anterior cervical spine surgery include gender, revision surgery, and multilevel surgery. The use of instrumentation, higher lev- els, or corpectomy versus discectomy did not significantly increase the preva- lence of dysphagia [43]. Ve r te br a l a r te r y i n ju r y is a rare (0.3%) complication in cervical discectomy [10]. However, in a report on 185 corpectomies, the vertebral artery was injured in four patients [18]. Posterior Approach to the Cervical Spine The anterior and posterior approaches are both frequently used to approach the cervical spine in a variety of disorders [58]. However, usually the anterior approach is preferred because of the minimal collateral soft-tissue damage. The posterior approach necessitates dissecting the neck muscles, which can be related to persistent postoperative neck pain. Indications The posterior approach to the cervical spine is predominantly indicated in cases with multisegmental degenerative changes or with craniocervical disorders ( Table 2): Table 2. Indications for the posterior approach to the cranio-cervical-thoracic spine (C0–T) spondylotic radiculopathy cervical fracture/instability spondylotic myelopathy chronic dens fractures cervical instability in rheumatoid arthritis tumors multisegmental degenerative changes infections spinal deformities Patient Positioning A Mayfield clamp is preferred for the headrest/fixation The positioning of the patient in the prone position is best accomplished using a Mayfield head clamp ( Fig. 3). The clamp is applied before turning the patient into the prone position. This fixation avoids pressure sores on the face, which are not infrequent when using other types of headrest (e.g. the horseshoe type). We use a carbon fiber clamp, which allows for anteroposterior imaging. The shoulders 342 Section Surgical Approaches Figure 3. Patient positioning for posterior cervical spine surgery Positioning of the patient with a Mayfield clamp and electrodes on the head for neuromonitoring. and arms (parallel to the body) are pulled down using nylon tapes to expose the cervical spine as much as possible. A footrest allows the whole table to be tilted head up, which accommodates the surgical approach. Surgical Exposure Landmarks for Skin Incision The landmarks of skin incision are: external occipital protuberance spinous processes C2–C7 The skin incision is along the midline from the external occipital protuberance towards caudal depending on the target region. When a short level exposure is attempted, image intensifier control is recommended to avoid unnecessary detachment of the posterior spinal muscles ( Fig. 4 a). Superficial Surgical Dissection After skin incision and splitting of the subcutaneous tissue, the superficial surgi- cal dissection should first identify the nuchal ligament. With a diathermy knife the muscles are detached subperiosteally from the spinous process. The superfi- cial muscle layer consists of ( Fig. 4 b): trapezius muscle posterior serratus muscle splenius capitis muscle Surgical Approaches Chapter 13 343 ab cd Figure 4. Surgical anatomy of the posterior cervical approach a Landmark for skin incision. b Superficial and intermediate muscle layers. c Exposure of the craniocervical junction with osteotomy of the spinous process for osteoligamentous muscle detachment. d Surgical anatomy at the craniocervical junction. The posterior cervical exposure can lead to significant bleeding Theintermediatemusclelayerconsistsof: semispinalis capitis muscle After sharp detachment the muscles are pushed laterally as one conglomerate with sponge rolls using a Cobb raspatory. Dissection of each muscle layer is unnecessary. In some patients, heavy bleeding is encountered which has to be borne in mind when performing this approach. Dense packing of the space between the spinous process and the laterally retracted muscles helps to control the bleeding. When the spine is exposed the bleeding usually stops, i.e. bleeding vessels can easily be identified and coagulated. During the superficial dissection 344 Section Surgical Approaches care has to be taken not to injure the greater occipital nerve (Fig. 4b), necessitat- ing a midline approach. Deep Surgical Dissection For exposure of the craniocervical junction, it is recommended to osteotomize with a chisel (or oscillating saw) the muscle insertion of the deep muscle layer from the spinous process of C2 ( Fig. 4c ). The deep muscle layer consists of cranially: rectus capitis posterior major and minor muscle oblique capitis inferior muscle and caudally: multifidus muscle semispinaliscervicismuscle The rationale for an osseous detachment is the better refixation of these muscles to counteract postoperative kyphosis. Exposure of the atlantoaxial joint jeopardizes the 2nd cervical nerve When exposing the craniocervical junction (Fig. 4d), care has to be taken not to injure the: vertebral artery second cervical nerve (greater occipital nerve) third cervical nerve The vertebral artery turns around the lateral mass of the atlas from lateral to medial and disappears into the foramen magnum through the atlanto-occipital membrane. The second cer vical nerve exits the spinal canal medial to the facet joint, crosses that joint posteriorly in a horizontal direction and curves around the oblique capitis inferior muscle before it runs cranially to innervate the occipital skin. The third cervical nerve exits the foramen and separates the posterior ramus, which runs medial to the second cervical nerve on its course to the occiput. Wound Closure In cases in which the insertion of the neck muscles has been detached from the tip of the spinous process with an osteoligamentous flap, a transosseous suture of the detached muscle is done with a slowly dissolving suture. The wound is closed with one or two subfascial suction drainages. The fascia, subcutaneous tissue and skin are sutured in separate layers. Pitfalls and Complications Exposure of C1 can cause vertebral artery injury The vertebral artery is at risk when a sublaminar wire is passed around the arch of C1. It is therefore mandatory to start in the midline to subperiosteally liberate the atlanto-occipital membrane from the bone with a blunt probe before the wire is passed with a wire passer (Dechamps). During the exposure of the atlantoaxial joint, the second cervical nerve is endangered because of its horizontal course over the posterior aspect. The craniocervical junction is highly vascularized by a large venous plexus. Blind coagulation may jeopardize the second or third cervical nerve. Right-Sided Thoracotomy The thoracotomy approach for the treatment of spinal disorders has been pio- neered by Capener [12] and Hodgson [19, 31, 32]. Today, it has become a stan- Surgical Approaches Chapter 13 345 If not determined by the pathology, the right sided approach is preferred dard approach for the treatment of thoracic spinal disorders including defor- mity, tumor or infection. In deformity surgery, the approach is always on the side of the apex of the curve, i.e. a right-sided thoracotomy is chosen for a right- sided curve. In cases in which the spinal pathology does not dictate the side of the thoracotomy, the right side is preferred because of the contralateral position of the aorta. Indications The indication for a thoracotomy is a spinal pathology located between T4 and T10 ( Table 3): Table 3. Indications for a thoracotomy (T4–T11) and thoraco-phrenico-lumbotomy (T9–L5) spinal deformities thoracic fractures/instabilities degenerative disorders tumors infections Patient Positioning The patient is positioned in a left-sided decubitus position on a soft rubber mat- tress. Alternatively, a vacuum mattress can be used which is helpful in large patients and better stabilizes the patient. Both arms are positioned at 90 degrees elevation and flexion of the elbow ( Fig. 5a, b). The legs are positioned straight with the right leg on top of the left leg. We use a foam rubber block with a cavity forthelowerleg.Therightlegcantheneasilybepositionedontopoftheblock. The symphysis and the sacrum are supported by pads to avoid the patient rolling over. Surgical Exposure Landmarks for Skin Incision Double-check the correct side of the thoracotomy A deleterious complication is awrong side thoracotomy. Therefore, it is manda- tory to double-check the side of the thoracotomy at the beginning of the sur- gery. Image intensifier control optimizes the spinal access Furthermore, it is of great importance to center the incision over the pathol- ogyandcorrectlyselectthetargetribortheintercostalspace.Therelationship between the intercostal space and the vertebral level is dependent on how oblique or horizontal the ribs curve to the sternum ( Fig. 6a). As a rule of thumb, the rib resected determines the highest vertebral level which can be reached (e.g. resec- tion of the 7th rib allows T7 to be reached). It best exposes the vertebra two levels below the origin of the resected rib (e.g. resection of the 7th rib allows the best exposure of T9). This is crucial when a mini-open exposure is attempted. Because of the variant forms of the ribcage, we recommend checking the correct level with an image intensifier. Nothing jeopardizes the success of an operation so much as an inappropriate exposure. Superficial and Intermediate Surgical Dissection The skin incision ranges from the lateral border of the paraspinous musculature to the sternocostal junction of the rib which has to be resected. After the incision of the subcutaneous tissue, the latissimus dorsi muscle and the anterior serratus muscle also have to be divided over the course of the target rib with a diathermy 346 Section Surgical Approaches a b Figure 5. Patient positioning for right-sided thoracotomy a Anterior view. b Posterior view. knife. It is recommended to only partially transect the latissimus dorsi muscle and lift it off the ribcage with a Hohman retractor ( Fig. 6 b). When exposing the anteriorpartoftheribcage,careshouldbetakentosparethe: long thoracic nerve (innervates the serratus muscle) Therefore, the serratus muscle should be dissected as far distally as possible. This is particularly important when high thoracic levels are exposed. The periosteum of the rib is dissected in the middle of the rib and liberated with a blunt dissector. A rib stripper is used to further liberate the rib. The rib is cut with a rib cutter as far posteriorly and anteriorly as possible to allow for a good exposure. When a thoracotomy is done with preservation of the rib, the intercostal muscle layer is cut in the lower half to preserve the neurovascular bundle which lies directly below the inferior edge. Surgical Approaches Chapter 13 347 ab cd ef Figure 6. Surgical anatomy for right-sided thoracotomy a Landmark for skin incision. b Superficial dissection. c Dissection of the rib for resection. d Exposure of the anterior spi- nal column. e Deep surgical dissection with ligation of the segmental vessels. f Insertion of a thorax drain and closure of the thorax. 348 Section Surgical Approaches Deep Surgical Dissection The parietal pleura is picked up with anatomical tweezers and opened with scis- sors. Depending on the necessary exposure, the anesthetist may then deflate the lung. The intercostal space is widened with a rib spreader ( Fig. 6d). The lung can be covered with an abdominal towel and retracted. The anterior vertebral col- umn becomes visible. The parietal pleura is lifted off the vertebral column with anatomical tweezers and opened to expose the segmental vessels ( Fig. 6e). The segmental vessels are mobilized with an overhold and ligated 3–4 cm anterior to the rib head. In severe spinal deformities the segmental vessel can first be clamped to see whether a ligation has an influence on the blood supply of the spi- nal cord, which would result in a decrease in evoked potentials (neuromonito- ring). A sponge stick is used to further expose the vertebral bodies and interver- tebral discs. Wound Closure Close the parietal pleura whenever possible The parietal pleura is sutured whenever possible and it is attempted to cover the implant with pleura. Before closing, one or two thorax drains are inserted. We recommend using large rather than small drains particularly when significant bleeding has occurred. Small drains are easily blocked by blood coagula. The skin is incised about one level below the target intercostal level in order to allow for an anatomical closure when removing the drain. A large towel clamp is inserted through the wound to pick up the drain and pull out the drain from the inside. The drain is manually placed at the apex of the thorax rather anteriorly. Depending on the bleeding, we prefer to insert a second drain, which is placed over the spine posteriorly. A rib approximator is used to narrow the ribs and fix them with a suture running around both ribs including the intercostal soft tissue but avoiding the neurovascular bundle ( Fig. 6f). We recommend placing all sutures first before tightening them. At this stage, the anesthetist is asked to rein- flate the lung. Care has to be taken that all parts of the lung are inflated to avoid atelectasis. If parts of the lung are not inflatable, a gentle manual massage of the lung tissue usually resolves this problem. The muscle and soft tissue layers cover- ing the ribcage are sutured sequentially. Pitfalls and Complications We have already mentioned the deleterious pitfall of opening the thorax on the wrong site (wrong site surgery).Theanteriorapproachtothespinecarriesa higher risk of serious complications than the posterior route for obvious reasons. The most frequent problems associated with this approach are: access through an intercostal space too high or too low in relation to the main pathology injury to the lung when incising the rib bed or opening the pleura injury to segmental vessels when exposing the spine injury to the azygos vein and aorta dissection into the intervertebral foramen Details on the handling of complications associated with this approach are cov- ered in Chapter 39 . Surgical Approaches Chapter 13 349 Left-Sided Thoraco-Phrenico-Lumbotomy This approach gives excellent access to the thoracolumbar junction This approach was introduced to spinal surgery by Hodgson mainly in the con- text of spinal tuberculosis [31, 32]. Similarly to a thoracotomy, an approach to the thoracolumbar junction is possible from the left as well as from the right side. When the pathology does not dictate the side of the approach, an access from the left side is preferred because the liver and the inferior vena cava are not hinder- ing the approach [11]. Indications If not determined by the pathology, the right sided approach is preferred The indication for a thoraco-phrenico-lumbotomy is a spinal pathology located between T9 and L5 and similar to those of a thoracotomy ( Table 3). Patient Positioning The patient is positioned on the right side inversely to a right-sided thoracotomy ( Fig. 7a, b).Thetablecanbeslightlybentabovethelevelofthepelvistoincrease the distance between pelvis and ribcage. Surgical Exposure Landmarks for Skin Incision Depending on the target level, it is usually recommended to resect the 10th rib (T10–L5). In cases with more proximal pathology, the 9th rib can be resected (T10–L5) ( Fig. 8a). Superficial Surgical Dissection After the incision of the skin and the subcutaneous tissue at the thoracolumbar junction, the superficial muscle layer is exposed consisting of ( Fig. 8b): serratus anterior muscle latissimus dorsi muscle external oblique muscle Whenever possible the muscles should be split in the direction of the fibers. Intermediate Surgical Dissection We recommend starting with the retroperitoneal approach. After splitting the externalobliquemuscle,theinternalobliqueandtransversusmusclesaresplit. With sponge sticks the peritoneal sac is mobilized to the midline and freed from the diaphragma. In a next step, the 9th or 10th rib is resected similarly to the method described above ( Fig. 6c ). The anterior resection is done close to the osseous-cartilage transition of the rib. The costal cartilage is split and the diaphragma is transected circumferentially about 2 cm medial to its insertion at the thorax wall. It is strongly recommended to use holding sutures bilateral to the transection to allow for a better orientation during diaphragma repair ( Fig. 8d, e ). 350 Section Surgical Approaches a b Figure 7. Patient positioning for left-sided thoraco-phrenico-lumbotomy a Anterior view. b Posterior view. Deep Surgical Dissection The left crus of the diaphragma is transected about 2 cm above the medial and lateral arcuate ligament. The parietal pleura is incised at the thoracic level as described above. The attachments of the psoas muscle need to be mobilized pos- teriorly. The vertebrae and intervertebral discs are further exposed with sponge sticks and rasps. The segmental vessels need to be ligated at the target level. Wound Closure At the thoracic level, the parietal pleura needs to be sutured. The repair of the diaphragma is facilitated when bilateral stay sutures were used during prior dis- Surgical Approaches Chapter 13 351 . all parts of the lung are inflated to avoid atelectasis. If parts of the lung are not inflatable, a gentle manual massage of the lung tissue usually resolves this problem. The muscle and soft. preferred dard approach for the treatment of thoracic spinal disorders including defor- mity, tumor or infection. In deformity surgery, the approach is always on the side of the apex of the curve, i.e. a. Therefore, it is manda- tory to double-check the side of the thoracotomy at the beginning of the sur- gery. Image intensifier control optimizes the spinal access Furthermore, it is of great importance