Cervical Vertebrae (Fig. 5-2)

Thoracic Vertebrae (Fig. 5-3)

Lumbar Vertebrae (Fig. 5-4)

Sacrum

Thoracic

Lumbar and Lumbosacral

Spinal Cord

Biopsy

Instrumentation

Superficial Dissection

Identify the platysma (Fig. 5-24)

• Divide the fibers of the platysma

• Alternatively, split the muscles of the platysma in line with fibers

• Elevate and mobilize the platysma superiorly and inferiorly as needed

Identify the anterior border of the sternocleidomastoid muscle (Fig. 5-25)

• Divide the fascia immediately anterior to the sternocleidomastoid muscle (deep cervical fascia)

Palpate the pulse of the carotid artery (Fig. 5-26)

• Divide the fascia immediately anterior to the carotid sheath (pretracheal fascia)

• Using blunt dissection, retract the sternocleidomastoid and carotid sheath (common carotid artery, internal jugular vein, and vagus nerve) laterally

• Retract the strap muscles (sternohyoid and sternothyroid) along with the trachea and esophagus medially

Continue with blunt dissection to develop the plane down to the anterior surface of the cervical vertebra (Fig. 5-27)

• Two arteries may be seen crossing the field from the carotid sheath toward the midline structures

• Superior thyroid artery

• Inferior thyroid artery

• One or both may have to be divided to increase surgical exposure

Deep Dissection

Deep dissection exposes the anterior cervical vertebra (Fig. 5-28)

• The longus colli muscles are now visible on either side

• The prevertebral fascia also can be seen covering the cervical vertebra

• The anterior longitudinal ligament can be seen as a gleaming white structure in the midline

• The sympathetic chain lies on the longus colli lateral to the vertebral bodies

Divide the prevertebral fascia

Detach and elevate the longus colli bilaterally for exposure

• At the level of the vertebral body, the anterior tubercle of the transverse process can help protect the vertebral artery

• Lateral dissection at the level of the disc should be performed carefully to reduce the risk of vertebral artery injury

Careful placement of the retractors deep to the longus colli reduces the risk of inadvertent injury to the surrounding structures

Intraoperative/Preincision Preparation

Pack the upper esophagus and trachea with sterile gauze

• Minimizes the ingestion of blood and other products

• Reduces the risk of aspiration

Careful retractor placement improves visualization of the interdental gap (Fig. 5-34)

• Elevate the soft and hard palate

• A malleable self-retainer or a soft rubber catheter can be placed through each nostril looped around the uvula

• Depress the tongue

• A tongue blade retractor can be used

Palpate the anterior tubercle of C1 in midline (Fig. 5-35)

• An intraoperative radiograph after positioning and prior to incision can help confirm the level and adequate exposure

• Confirm the location radiographically

Incision

A 1- to 2-cm vertical longitudinal midline incision (Fig. 5-36)

• Just proximal to the anterior C1 tubercle down onto the body of C2 distally

Make an “H” incision (Fig. 5-37)

• Vertical limbs are placed as far lateral as possible

• Injury to the eustachian tubes can occur if the vertical limbs are too lateral

• Allows for two broad-based pharyngeal myomucosal flaps that are elevated superiorly and inferiorly

• The horizontal limb is based on the level of the soft palate

Closure

Correction of Deformity

Other Indications

Positioning

Lateral decubitus position with the side to be approached oriented up (Fig. 5-44)

• For deformity, the convexity of the curve is typically oriented up

• For decompressions, the side with the greatest stenosis to be addressed is typically oriented up

Secure the patient firmly to the operating table

• Stabilize the patient with either beanbags or hip positioners

• Carefully note the orientation of the spine before draping

• Noting the orientation reduces the risk of disorientation and inadvertent entry into the spinal canal

• Noting the orientation is particularly important if rotation of the table is required intraoperatively

• Place a well-padded small roll in the axilla of the dependent side to avoid prolonged axillary artery, vein, and brachial plexus compression

• Place the hand and arm on the side to be approached above the head

Incision

It is easier to extend the dissection distally than proximally

• It is best to center the incision on the rib associated with the vertebra of interest or the one more superior (Fig. 5-45)

• The rib articulates with the corresponding vertebra and the one more cranial

• The eighth rib typically articulates with the T7 vertebra and the T8 vertebra

• Correlate the number of ribs from preoperative imaging with the number of ribs palpated on the patient after positioning

• Typically, the twelfth rib cannot be felt, and the most inferior rib palpated is the eleventh rib

• The tip of the scapula is mobile and varies in location; however, an incision centered approximately one to two fingerbreadths below the tip usually overlies the seventh or eighth rib

Superficial Dissection

Identify the latissimus dorsi and trapezius muscles (Fig. 5-46)

• Divide the latissimus dorsi in line with the skin incision

• Because this division is not performed in the intramuscular plane, bleeding can be an issue

• The scapula can now be elevated

• Although it is unnecessary, the surgeon can carefully develop the plane between the scapula and ribs to obtain confirmation of the appropriate rib level

• The most proximally palpated rib is typically the second rib

• If necessary, the rhomboids can be detached to improve the posterior exposure

The serratus anterior can now be better identified (Fig. 5-47)

• Divide the serratus anterior in line with the incision to expose the rib

Subperiosteally elevate the musculature from the ribs (Fig. 5-48)

• Detachment of the muscular attachments

• Above the rib, proceed posterior to anterior (Fig. 5-49)

• Below the rib, proceed anterior to posterior

• If possible, preserve the intercostal neurovascular bundle, which runs along the inferior border of the rib

• Continue the subperiosteal dissection as far posteriorly as necessary

• Using a rib cutter, resect as much rib as necessary to obtain the needed exposure

• Bleeding at the posterior angle of the rib after it is resected can be controlled with bone wax

• Save the rib to use as a bone graft if one is needed

The thoracic cavity can be entered now by cutting the periosteum and pleura above the rib (Fig. 5-50)

• Notify the anesthesia team at this point that you are entering the chest

Deep Dissection

Insert a rib spreader

The lung can be readily identified

• Typically, use of a double-lumen tube is unnecessary

• Pack moist laparotomy sponges to assist in the exposure

Identify the posterior mediastinum and associated structures (Fig. 5-51)

• The lateral aspect of the spine can be readily identified

• The “hills” are the intervertebral discs

• The “valley” is the vertebral body

Incise the pleura (Fig. 5-52)

• Allows for mobilization of the posterior mediastinal structures off the anterior aspect of the vertebra

• The intercostal vessels can be seen crossing the operative field at the level of the midvertebral body

• Preserve the intercostal vessels if possible

• Tying off more intercostal vessels than necessary should be avoided

Closure

Correction of Deformity

Other Indications

Hazards

Incision (Fig. 5-53)

Superficial Dissection

Identify the latissimus dorsi (Fig. 5-54)

• Divide the latissimus dorsi in line with the skin incision

• Because this division is not performed in the intramuscular plane, bleeding can be an issue

The serratus anterior can be better identified now

• Divide the serratus anterior in line with the incision to expose the rib

Subperiosteally elevate the musculature from the ribs

• Detachment of the muscular attachments

• See the thoracic approach

The thoracic cavity can be entered now by cutting the periosteum and pleura above the rib

• Notify the anesthesia team at this point that you are entering the chest

Split the costal cartilage with a knife along its length (Fig. 5-55)

• The preperitoneal fat can be visualized at this time

• Bluntly dissect the peritoneum off the inferior surface of the diaphragm

• Sweep peritoneum from the undersurface of the diaphragm and the transversalis fascia and abdominal wall

Next, the three abdominal muscles are sequentially encountered: external oblique, internal oblique, and transversus abdominis (Fig. 5-56)

• Open abdominal musculature—aponeurosis of external oblique, internal oblique, transversus abdominis, and transversalis fascia

• See the anterior retroperitoneal approach to the lumbar spine

Incise the diaphragm (Fig. 5-57)

• Detach the diaphragm approximately 2 cm from its peripheral attachment to the chest wall

• Mark the diaphragm with suture or ligature clips to allow for accurate reapproximation

• For added exposure, complete separation of the diaphragm can be performed by dividing the medial and lateral arcuate ligaments and the crus of the diaphragm

Deep Dissection

Insert a rib spreader and abdominal retractor into the respective cavities (Fig. 5-58)

Thoracic cavity (see the thoracic approach)

• The lung can be readily identified

• Identify the posterior mediastinum and associated structures

• The lateral aspect of the spine can be readily identified

• Incise the pleura

• The intercostal vessels can be seen crossing the operative field at the level of the midvertebral body

Abdominal cavity (see the anterior retroperitoneal approach)

• Identify the psoas fascia, but do not enter the muscle

• Identify and preserve the genitofemoral nerve

• Identify and, if possible, preserve the sympathetic chain

• Identify the segmental vessels as they cross the field at the level of the midvertebral body

Closure

Other Indications

Incision

Identify the pubic symphysis, ASIS, and inferiormost rib (Fig. 5-62)

• Correlate the number of ribs from preoperative imaging with the number of ribs palpated on the patient after positioning

• Typically the twelfth rib cannot be felt, and the most inferior rib palpated is the eleventh rib

Identify the umbilicus and palpate the lateral border of the rectus abdominis muscle

Design the skin incision based on the bony landmarks and the corresponding spinal level to be addressed

• Multiple incisions are described

• Transverse (Pfannenstiel) incision (Fig. 5-63)

• Longitudinal incision (Fig. 5-63)

• Oblique flank incision (Fig. 5-62)

Superficial Dissection (Fig. 5-64)

Deep Dissection

Identify the psoas fascia, but do not enter the muscle (Fig. 5-65)

• If a psoas abscess is present, it can be palpated easily at this point and entered with gentle finger dissection

• If a transpsoas approach is planned, neuromonitoring should be considered to reduce the risk of lumbosacral plexus injury because the lumbosacral plexus typically runs in the posterior aspect of the psoas (Fig. 5-66)

Identify the genitofemoral nerve

• Typically, the genitofemoral nerve is lying on the anteromedial aspect of the psoas within the psoas fascia

• This nerve should be preserved

Identify the sympathetic chain

• The sympathetic chain lies even more anterior and medial to the genitofemoral nerve

• Typically, the sympathetic chain lies anterior to the psoas on the lateral aspect of the vertebral body

• Preserve the sympathetic chain if possible

• Division of the sympathetic chain results in a warm leg on the ipsilateral side of the surgical approach

• Postoperatively, the more commonly identified complaint is a relatively cool contralateral lower extremity

Identify the segmental vessels as they cross the field at the level of the midvertebral body (Fig. 5-67)

• Depending on the procedure to be performed, these vessels can be either spared or tied and cut

• Access to the anterior portion of the vertebral bodies requires mobilization of the great vessels by ligating the segmental vessels

• Do not cut the lumbar segmental vessels flush with the great vessels

• For the L5-S1 disc, and occasionally the L4-5 disc, a transperitoneal lumbar approach also can be used (see the transperitoneal approach)

• Identifying the iliolumbar vein is important, particularly for approaches to the L4-L5 disc space

Closure

Fusion

Other Indications

Landmarks

Hazards

Incision (See Fig. 5-63)

Superficial Dissection

Deepen in line with the skin incision down to the rectus sheath

Identify the rectus sheath (Fig. 5-68)

• Incise the sheath in the midline in line with the skin incision

• The linea alba marks the midline of the rectus abdominis muscles

• This landmark is typically more apparent above the umbilicus and less distinct below it

Enter the peritoneal cavity (Fig. 5-69)

• The linea alba may be divided in the midline

• Next, bluntly dissect between the rectus muscles with your fingertips

• Alternatively, the rectus fascia may be divided longitudinally over its lateral margin

Mobilize the rectus medially to expose the posterior rectus fascia

Entering lateral to the rectus allows the surgeon to proceed with either a transperitoneal or a retroperitoneal approach to the lumbar spine

• Identify and carefully incise the peritoneum

• Avoid injury to the underlying structures

• The dome of the bladder is at risk if the incision is distal and deep

• Placing one hand or a moist laparotomy sponge within the abdominal cavity helps protect the viscera

Deep Dissection

Insert an abdominal self-retainer

• Assists in retracting the rectus abdominis and the bladder

• Additional blades may be inserted as needed to provide access to the deep structures

• Place moist laparotomy sponges between the blades and the abdominal contents to reduce the risk of iatrogenic visceral injury

The posterior peritoneum can be seen overlying the retroperitoneal structures (Fig. 5-70)

• Identify the common iliac vein and artery underneath the peritoneum

• Typically, the bifurcation lies at the level of the L4-L5 intervertebral disc or the L5 body

• Identify the ureter passing over the pelvic brim bilaterally

• This structure can be confirmed by gently pinching it with a pair of nontoothed forceps to induce peristalsis

• Palpate the sacral promontory through the posterior peritoneum

Open the posterior peritoneum by incising it over the sacral promontory (Fig. 5-71)

• Ligate the middle sacral artery, which runs down the anterior sacrum

• Presacral sympathetic nerves (superior hypogastric plexus) also run in this area

• Although variable, most of the fibers overlie the left iliac vessels

• Injury to these nerves may result in retrograde ejaculation and impotence in men

• Expose the presacral space using blunt dissection as much as possible

• Limit the use of monopolar electrocautery if possible

Identify the L5-S1 disc and the sacral promontory

• Confirm the level with an intraoperative radiograph if necessary

Closure

Posterior Occipitocervical Fusions and C1-C2 Fusions

Superficial Dissection

Divide subcutaneous fat and deep cervical fascia in line with the skin incision (Fig. 5-74)

Identify the nuchal ligament

• This plane is relatively avascular and is typically seen as a thin white line in the midline

• Because the posterior cervical musculature is extremely vascular, the dissection should remain in the midline to reduce bleeding

• The third occipital nerve is rarely at risk; however, it can be at risk if the superficial dissection strays to the midline

Deepen the incision to the external occipital protuberance and down to the posterior tubercle of C1 and the bifid spinous process of C2 and C3

• The ring of C1 has no spinous process

• The dissection should be performed carefully to prevent inadvertently entering the spinal canal

Closure

Posterior Spinal Fusion

Positioning

Hazards

Incision

Longitudinal midline (see the posterior approach to the occipitocervical junction; Fig. 5-80)

Superficial Dissection

Divide subcutaneous fat and deep cervical fascia in line with the skin incision (Fig. 5-81)

Identify the nuchal ligament (see previous description)

The supraspinous and interspinous ligaments should be protected during the initial dissection

Subperiosteally, follow the spinous process out laterally first onto the lamina and then to the lateral mass (Fig. 5-82)

If possible, protect the facet capsule unless a fusion is to be performed at that level

The lateral mass is the rectangular mass of bone that lies between the superior articular and inferior articular facet of the same vertebra

• The starting point of lateral mass screws is 1 mm medial of the center of the lateral mass angulated superiorly (approximately 15 degrees) and laterally (approximately 30 degrees)

Exposure of the cervicothoracic junction

• The posterior cervicothoracic junction typically can be identified by the characteristic bony landmarks

• Because the transverse process of the cervical vertebra lies more anteriorly, it is typically not seen during the exposure of the C7 lateral mass

• This situation is in contradistinction to the T1 transverse process, which is readily identified and travels in a lateral superior direction and is partially overlapped by the C7 lateral mass, giving the C7-T1 junction a distinct anatomic appearance (Fig. 5-83)

Deep Dissection

Laminectomy or Laminotomy (Fig. 5-84)

Typically, this procedure can be performed using a No. 1 or 2 Kerrison rongeur, depending on the space available and the thickness of the lamina

If the lamina is too thick, it can be carefully thinned using a rongeur or power burr

The epidural fat overlying the translucent blue-white dura is visible after the ligamentum flavum and lamina are removed

Multilevel Laminectomies

Thin the lamina at the laminofacet junction at each level of interest with use of a power burr, creating a trough bilaterally

Complete the trough using a 1- or 2-mm Kerrison rongeur

Carefully remove the ligamentum flavum at the superior and inferior edges of the decompression

Carefully remove the lamina en bloc using multiple towel clips secured into the spinous processes

Depending on the level, consideration should be given to placement of either lateral mass or pedicle screws (Fig. 5-85)

Keyhole Laminoforaminotomy

Create a laminotomy at the level of interest, as described previously (Fig. 5-86)

• Center half of the laminotomy in the inferior lamina of the vertebra above and the other half in the superior lamina of the vertebra below

• This procedure forms the circular portion of the “keyhole”

Trace the path of the exiting nerve root with a Woodson instrument or nerve hook

Using a power burr, thin the medial 50% of the facet joint (Fig. 5-87)

• Perform this maneuver from a medial to lateral direction

• Remove the remaining thinned bone with a Kerrison rongeur

• Do not remove more than 50% of the facet

• If more than 50% is removed, a fusion should be included

Pedicle screw fixation is not routinely placed in the cervical spine

• In selected cases, pedicle screws can be placed at levels from C2 to C7

• Lateral mass screws are typically used from C3 to C6

Epidural bleeding can be brisk and difficult to control during any portion of the deep dissection

• Use of thrombostatic agents and Neuropaddies typically can control most bleeding

Closure

Spinal Fusion

Other Indications

Hazards

Incision

Palpate the spinous processes in the midline (Fig. 5-94)

Confirm the level with intraoperative radiographs to help plan the surgical incision

Several skin incisions have been described

• Midline longitudinal over the spinous process

• This approach is completely extensile and utilitarian for revisions but may need to be extended in length to achieve adequate lateral exposure

• Paramedian longitudinal

• Approximately 2.5 cm lateral to the spinous process

• Curvilinear

• Approximately 10 to 12 cm in length with the apex 6 to 8 cm lateral to the midline centered at the level of the diseased area

• “T” incisions also have been described but are typically not required

Superficial Dissection

Divide subcutaneous tissue in line with the skin incision

• If a midline approach is used, then this exposure will be analogous to the posterior midline approach to the thoracic spine

• Superiosteally dissect off the paraspinous musculature either bilaterally or unilaterally, depending on the pathologic condition being addressed (see Fig. 5-90)

• Expose the lamina and transverse processes out to the tip (see Fig. 5-91)

• Expose onto the rib and rib–transverse process articulation (Fig. 5-95)

• Subperiosteally dissect the fascia, muscle attachments, and periosteum circumferentially around the rib

• If a paramedical approach is used, then a slightly more lateral approach and plane is developed

• Identify the trapezius as the next muscle layer, and split it in line with the incision (Fig. 5-96)

• The trapezius is innervated by the spinal accessory nerve proximally and is not denervated

Next, identify the erector spinae and transversospinales muscles (deep paraspinal muscles), and divide these muscles in line with the incision (Fig. 5-97)

• These muscles are segmentally innervated and are not significantly denervated by this approach

Identify the junction of the rib–transverse process articulation (see Fig. 5-95)

• Subperiosteally dissect the fascia, muscle attachments, and periosteum circumferentially around the rib

Deep Dissection

The amount of rib resection varies based on the exposure required (2 to 8 cm of rib from the midline; Fig. 5-98)

• Because of the numerous ligamentous attachments between the rib and transverse process and the rib head and spine, removal of the rib can be difficult

If wider exposure is required, detach the muscular attachments to the transverse process and remove the process at the base

Enter the retropleural space and identify the lateral vertebral body and corresponding disc space (Fig. 5-99)

• The retropleural space can be entered by careful subperiosteal dissection along the lateral pedicle wall onto the lateral vertebral body wall

• Avoid entering the pleural cavity if possible

• Rotating the patient away from the side of the surgical exposure can improve visualization of the lateral aspect of the vertebral body

• This maneuver can be performed at several levels as necessary

Closure

Posterior Spinal Fusion

Osteotomy

Other Indications

Superficial Dissection

Divide the fat and fascia in line with the skin incision (Fig. 5-104)

Palpate for the spinous process intermittently to help identify the midline

• This palpation is particularly important in larger patients and patients with scoliotic deformity

Using a Cobb elevator, dissect down to the spinous process

Detach the paraspinous muscles subperiosteally from the midline (Fig. 5-105)

• Subperiosteal dissection helps reduce bleeding

• In young patients, the tips of the spinous process are cartilaginous apophyses

• These cartilaginous apophyses can be split or detached to assist in the subperiosteal muscle dissection

• In adults, the supraspinous and interspinous ligaments should be preserved if possible to reduce the risk of junctional kyphosis

Follow the spinous process laterally to the lamina and out to the facet joint capsule (Fig. 5-106)

• If a fusion is not planned, preserve the facet joint and overlying capsule

• Facet joints in the lumbar spine are oriented in a parasagittal plane

• The inferior articular facet of the superior vertebra lies medial and posterior to the superior articular facet of the inferior vertebra

Identify the pars interarticularis

• This structure lies between the superior and inferior articular facet of the same vertebra

If necessary, the dissection can be continued laterally to the mammillary process, then onto the transverse process

• Care should be taken to stay on the transverse process. Straying inadvertently deep to the intertransverse ligament can result in injury to the exiting nerve root

• Occasionally, excision of a far lateral disc requires that the intertransverse ligament be divided

• Dissection lateral to the facet joint may result in injury to the articular branches of the segmental vessels

• This dissection would not cause a problem; however, these vessels can bleed vigorously and should be controlled with careful cauterization or packing

Deep Dissection

Identify the ligamentum flavum (Fig. 5-107)

• The superior attachment is on the superior lamina halfway up its anterior/undersurface

• The canal can be entered superiorly by removing the distal end of the superior lamina with a Kerrison rongeur until the attachment of the ligamentum flavum is reached

• The inferior attachment on the inferior lamina is at its superior (leading) edge

• The canal can be entered inferiorly by cutting the attachment of the ligamentum flavum directly from the leading edge of the inferior lamina

Variable amounts of epidural fat are seen upon entering the spinal canal

Immediately beneath the epidural fat is the blue-white dura

Success for almost all procedures in the lumbar spine lies in identifying the location of the pedicle (Fig. 5-108)

• The disc space lies just superior to the pedicle

• The exiting nerve root first travels just medial to the pedicle and then exits the foramen just inferior to the pedicle

Identify the pars interarticularis

• The pars interarticularis should be exposed and defined during the superficial dissection

• If no fusion is to be performed, care should be taken not to remove too much of the pars interarticularis during the laminotomy and foraminotomy

• Complete resection of the pars interarticularis results in an iatrogenic spondylolysis and possible spondylolisthesis

• Bilateral pars defects result in segmental instability and an iatrogenic spondylolisthesis

Laminotomy/laminectomy (Fig. 5-109)

• Depending on the etiology and location of the spinal compression, a laminotomy (windowing), a laminectomy, or a variation of the two can be used to gain access to the spinal canal (Fig. 5-110)

Discectomy

• Before surgery, preoperative imaging should be studied carefully to understand fully the location of the herniated disc

• The most common location for disc herniations remains posterolateral

• A natural weakening occurs just lateral to where the posterior longitudinal ligament begins to thin

• Posterolateral herniations typically impinge on the shoulder of the nerve root, traversing that level to the more inferior vertebra

Foraminotomy

• In the case of neuroforaminal stenosis, direct nerve impingement can result from facet capsule hypertrophy or bony osteophytes

• This typically results in impingement of the nerve root exiting at that level

Identification of the lumbar pedicle (Fig. 5-111)

• Use of fluoroscopic guidance can assist in pedicle localization

• Anatomic landmarks for the pedicle entry site

• Variations exist, but typically the entry site can be identified by the confluence of several lines

• The line bisecting the midpoint of the transverse process

• The lateral edge of the superior articular facet

• The superomedial edge of the mammillary process

• A curvilinear line following the pars proximally to the crossing point of the other lines

Closure

Positioning

Landmarks

Incision (Fig. 5-116)

Superficial Dissection

Deepen in line with the skin incision down to the iliac wing

• Do not stray anterior to the ASIS

• Lateral femoral cutaneous nerve

• Course varies

• Typically, it runs 1 cm anterior to the ASIS underneath the inguinal ligament

• Inguinal ligament

• Takes origin off of the ASIS

• Do not inadvertently cut or detach the inguinal ligament, which can result in an inguinal hernia

Identify the natural raphe between the fascia overlying iliac wing (Fig. 5-117)

• Fascia of external oblique anteriorly

• Fascia of gluteus medius posteriorly

Incise directly on the iliac wing

Closure

Landmarks

Incision

A variety of incisions are described (Fig. 5-120)

• All separate surgical incisions are centered on the PSIS

• Alternatively, can be obtained from same midline incision as the primary procedure

Closure