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7 Patient Selection
57
Fig. 7.2 Class 2 patient. A 66-year-old F presents with
back and leg pain. She had minimal central canal stenosis
with foraminal stenosis at multiple levels. Preoperative
x-rays demonstrated PI 43°, PT 20°, LL 22°, TK 24°, SVA
5 cm, and coronal imbalance 2.4 cm. She underwent a
(PT), and LL-PI mismatch) were presented to the
surgeons. Three cases were consistent with
MISDEF Class I, ten cases were consistent with
MISDEF Class II, and seven cases were consistent with MISDEF Class III. The results were
tabulated and the cases were re-presented
2 months later in a new order and the results
again tabulated. Fleiss kappa coeffi cient analysis
was used to determine both intraobserver and
interobserver reliability. There was an interobserver kappa of 0.58 for the fi rst round of surveys
and an interobserver kappa of 0.69 for the second
round of surveys consistent with substantial
L2/3, L3/4, L4/5 LLIF with L2-sacroiliac fi xation through
a minimally invasive posterior approach. Postoperative
scoliosis fi lms demonstrated PI 43°, PT 15°, LL 34°, TK
31°, SVA 2 cm, and coronal imbalance 1 cm
agreement. The mean intraobserver kappa for the
two surveys was 0.86 ± 0.15 (±SD) and ranged
from 0.62 to 1.
Strengths of this algorithm include its simplicity, moderate intraobserver and interobserver reliability. Limitations include that it
has not been validated in relation to radiographic and health-related quality-of-life outcomes. Additionally, not all deformities can be
appropriately treated with a minimally invasive
technique. This system accounts for this with
the class III deformities being recommended
for treatment with open techniques.
58
T.D. Vogel and P.V. Mummaneni
Fig. 7.3 Class 3 patient. A 60-year-old M presents with
back and leg pain. MRI demonstrated spinal stenosis compounded by adult spinal deformity with a PI-LL mismatch. Preoperative x-rays demonstrated PI 38°, LL -4°,
PT 29°, TK 10°, SVA 8.5 cm, and coronal imbalance
References
1. Acosta FL, Liu J, Slimack N, Moller D, Fessler R,
Koski T. Changes in coronal and sagittal plane alignment following minimally invasive direct lateral interbody fusion for the treatment of degenerative lumbar
disease in adults: a radiographic study. J Neurosurg
Spine. 2011;15:92–6.
2. Glassman SD, Hamill CL, Bridwell KH, Schwab FJ,
Dimar JR, Lowe TG. The impact of perioperative
complications on clinical outcome in adult deformity
surgery. Spine (Phila Pa 1976). 2007;32:2764–70.
3. McAfee PC, Regan JJ, Geis WP, Fedder IL. Minimally
invasive anterior retroperitoneal approach to the lumbar spine. Emphasis on the lateral BAK. Spine (Phila
Pa 1976). 1998;23:1476–84.
4. Mummaneni PV, Haid RW, Rodts GE. Lumbar interbody fusion: state-of-the-art technical advances.
Invited submission from the joint section meeting on
disorders of the spine and peripheral nerves, March
2004. J Neurosurg Spine. 2004;1:24–30.
−3.9 cm. He underwent a posterior T9 to sacrum fusion
with L3 PSO, T9−11 and L1−L5 laminectomy, and iliac
fi xation. Postoperative x-rays demonstrated PI 39°, LL
32°, PT 14°, TK 9°, SVA 4.3 cm, and coronal imbalance
3.5 cm
5. Mummaneni PV, Shaffrey CI, Lenke LG, Park P,
Wang MY, La Marca F, Smith JS, Mundis Jr GM,
Okonkwo DO, Moal B, Fessler RG, Anand N, Uribe
JS, Kanter AS, Akbarnia B, Fu K, Minimally Invasive
Surgery Section of the International Spine Study,
G. The minimally invasive spinal deformity surgery
algorithm: a reproducible rational framework for
decision making in minimally invasive spinal deformity surgery. Neurosurg Focus. 2014;36:E6.
6. Mummaneni PV, Tu TH, Ziewacz JE, Akinbo OC,
Deviren V, Mundis GM. The role of minimally invasive techniques in the treatment of adult spinal deformity. Neurosurg Clin N Am. 2013;24:231–48.
7. Nacar OA, Ulu MO, Pekmezci M, Deviren V. Surgical
treatment of thoracic disc disease via minimally invasive lateral transthoracic trans/retropleural approach:
analysis of 33 patients. Neurosurg Rev. 2013;36:
455–65.
8. Ozgur BM, Aryan HE, Pimenta L, Taylor
WR. Extreme Lateral Interbody Fusion (XLIF): a
novel surgical technique for anterior lumbar interbody
fusion. Spine J. 2006;6:435–43.
7 Patient Selection
59
9. Schwab FJ, Hawkinson N, Lafage V, Smith JS, Hart
R, Mundis G, Burton DC, Line B, Akbarnia B,
Boachie-Adjei O, Hostin R, Shaffrey CI, Arlet V,
Wood K, Gupta M, Bess S, Mummaneni PV,
International Spine Study, G. Risk factors for major
peri-operative complications in adult spinal deformity
surgery: a multi-center review of 953 consecutive
patients. Eur Spine J. 2012;21:2603–10.
10. Silva FE, Lenke LG. Adult degenerative scoliosis:
evaluation and management. Neurosurg Focus.
2010;28:E1.
11. Tormenti MJ, Maserati MB, Bonfi eld CM, Okonkwo
DO, Kanter AS. Complications and radiographic correction in adult scoliosis following combined transpsoas extreme lateral interbody fusion and posterior
pedicle screw instrumentation. Neurosurg Focus.
2010;28:E7.
12. Wang MY, Mummaneni PV. Minimally invasive surgery for thoracolumbar spinal deformity: initial clinical experience with clinical and radiographic
outcomes. Neurosurg Focus. 2010;28:E9.
Positioning and Safety
Viren S. Vasudeva , Muhammad M. Abd-El-Barr ,
Yi Lu , and Michael W. Groff
8
8.1 Introduction
The lateral decubitus position has classically
been used in spine surgery to gain lateral access
to the vertebral column via thoracotomy and retroperitoneal approaches [ 1 , 2 ]. In some cases –
particularly those requiring corpectomy – a
lateral approach is preferred to gain suffi cient
access with decreased risk to the neural elements
compared to posterior approach. Currently, with
the rising popularity of the minimally invasive
lateral lumbar interbody fusion which was developed in the 2000s, it is more important than ever
for spine surgeons to understand proper lateral
decubitus positioning in order to optimize exposure and minimize the risk of iatrogenic injury to
the patient [ 3 – 5 ].
V. S. Vasudeva • M. M. Abd-El-Barr • Y. Lu
Department of Neurosurgery , Brigham & Women’s
Hospital, Harvard Medical School ,
75 Francis Street , Boston , MA 02115 , USA
M. W. Groff (*)
Harvard Medical School , Boston , MA , USA
mgroff@mac.com
e-mail:
8.2 Positioning the Patient
Although patient positioning for surgery may
become a routine process, it is crucial that it is
performed properly before every case. Optimizing
the exposure of the operative site will enable the
surgeon to carry out the operation more smoothly.
Additionally, with the patient immobilized under
anesthesia, the combined factors of time and
mechanical pressure can result in skin breakdown, pressure ulcers, or peripheral nerve injury.
These types of iatrogenic injuries must be avoided
in order to ensure a good outcome for the patient
and to prevent potential litigation [ 6 – 8 ].
Prior to positioning, the patient is anesthetized
and intubated while supine on a stretcher. With
the help of other team members, the patient is
then transferred to the OR table and turned to the
lateral position with the dependent arm outstretched. Before moving the patient, the OR
table should be prepared either with a draw sheet
(to support chest rolls), or a vacuum bean-bag
positioning device, or a lateral positioner. At this
point, it is important to ensure that the patient is
centered on the OR bed and that the iliac crest is
in line with a break in the bed so that when the
bed is fl exed, the distance between the twelfth rib
and the ilium is enlarged thereby increasing the
operative window (Fig.
8.1 ).
© Springer International Publishing Switzerland 2017
M.Y. Wang et al. (eds.), Lateral Access Minimally Invasive Spine Surgery,
DOI 10.1007/978-3-319-28320-3_8
61
62
Fig. 8.1 Patient in the lateral
decubitus position
V.S. Vasudeva et al.
Pillows, blankets, or a gel donut are then
placed beneath the patient’s head to support it in
a neutral position. The patient’s eyes, especially
the dependent eye, should be checked to ensure
that they are free of pressure which could lead to
postoperative blindness. The downward facing
ear should be checked to ensure that it is not bent.
The patient’s chest is then lifted, and a small axillary roll is placed beneath the patient’s upper
ribs. The axillary roll functions to raise the
patient’s chest off of the OR bed and remove
mechanical compression of the neurovascular
structures in the patient’s axilla. This will allow
room for expansion of the chest wall during respiration, adequate blood fl ow to the dependent
arm, and will prevent brachial plexus traction. If
the axillary roll is placed too high, the roll itself
could cause compression of the structures in the
axilla which it is designed to protect. By palpating the radial artery pulse on the patient’s dependent arm, the surgeon can ensure that the axillary
role is not impeding the blood fl ow through the
axillary or brachial artery (Figs.
8.2 and 8.3 ).
Next, the patient’s chest and abdomen are supported in the lateral position by tightening the
draw sheet around chest rolls placed on either
side of the patient. If a vacuum bean-bag positioning device is used, it should be molded around
the patient’s body, and negative pressure should
be applied to create a rigid structure. If the patient
is female, care should be taken to ensure that her
breasts are free and particularly that there is no
pressure on the nipples.
The patient’s dependent arm, which is outstretched, is then supported by an armrest and
padded with a foam or gel pad. By keeping this
arm in supination, the ulnar nerve is protected as
it passes through the cubital tunnel [ 5 ]. The upper
arm is secured to an arm board with shoulder
fl exion ≤90° [ 6 ].
A foam or gel pad is placed under the dependent knee. This provides some protection to the
common peroneal nerve as it crosses over the
head of the fi bula. A pillow is placed in between
the patient’s legs and feet. Both legs are placed
in slight fl exion which provides stability to the
patient’s pelvis and reduces tension on the
psoas muscle and the nerves of the lumbar
plexus. Another pad is placed under the
patient’s feet. When positioning has been completed, Velcro safety straps are passed over the
patient’s hip and shoulder to provide further
stability. Three-inch silk tape may be used as
well to increase stability, and some surgeons
prefer to cross the tape over the patient’s legs
as seen in Fig.
8.1 . If the shoulder tape lays
over the patient’s upper arm, the elbow and
radial groove of the humerus should be avoided
in order to prevent injury to the ulnar or radial
nerves respectively [ 10 , 11 ]. Padding may be
placed under the tape to protect the patient’s
skin.
8 Positioning and Safety
Fig. 8.2 Image illustrating
the proper placement of the
patient’s arms and head in the
lateral decubitus position.
Note that the head is elevated
so that the cervical spine
remains in neutral alignment
and that the eyes are free from
external pressure
Fig. 8.3 Placement of the
axillary roll in the lateral
decubitus position. The roll is
placed underneath the upper
ribs and not within the axilla
itself where it would cause
direct compression of the
axillary artery and brachial
plexus
63
Finally, the bed may be placed into slight fl exion as described above based on the surgeon’s
preference. If this maneuver is performed with
the bed already in the reverse Trendelenburg
position, the surgeon can ensure that the patient’s
upper body remains parallel to the ground [ 10 ]. It
has been suggested that increasing the amount of
fl exion of the bed results in higher skin-to- surface
interface pressures and this may increase the likelihood of pressure ulcer formation or rhabdomyolysis [ 12 ]. Before beginning the case,
fl uoroscopy should be used to ensure that there
will be proper visualization of the surgical target.
For minimally invasive surgeries, it is critical to
obtain good fl uoroscopic images. To obtain a true
lateral image, the C-arm is brought in perpendicular to the fl oor (90°). The table is then placed in
Trendelenburg or reverse Trendelenburg until a
true lateral image with linear endplates and
superimposed pedicles is achieved. Following
this, the C-arm is rotated so that it is parallel to
the fl oor in order to obtain a cross-table AP image
(0°). The left-right tilt of the table is adjusted
until a true AP image with midline spinous processes and symmetric pedicles is achieved. This
process may be especially complicated in patients
with scoliosis where there is often axial rotation
of the spinal segments; however, ensuring that
64
Fig. 8.4 Patient in the lateral
decubitus position with the
bed fl exed. Note that the point
of fl exion is underneath the
iliac crests which allows for
an improved retroperitoneal
exposure
V.S. Vasudeva et al.
the patient is in the true lateral position with good
fl uoroscopic images will help the surgeon to
avoid inadvertently damaging the endplates,
neural structures, and visceral or vascular structures anterior to the spine during lateral surgery
(Fig. 8.4 ).
8.3 Complications Associated
with Patient Positioning
8.3.1 Pressure Ulcers
Pressure ulcers have been reported to occur in
anywhere from 8.5 to 66 % of patients in the
immediate postoperative period [
Schultz et al. found that 89 out of 413 (21.5 %)
surgical patients developed pressure ulcers over
six postoperative days. These ulcers were primarily stage I and were more likely to occur in
patients who were older, had diabetes, and who
had smaller body mass [ 16 ]. The development of
these ulcers is also related to the length of the
surgery [ 5 , 13 ].
Pressure ulcers occur when external pressure
is so great that subcutaneous blood fl ow is compromised to the point where the skin and subcutaneous tissue hypoperfusion results in tissue
ischemia and eventually necrosis. More specifi cally, ulcers occur when the external pressure
exceeds the capillary fi lling pressure of
6 , 13 – 17 ].
~32 mmHg. Longer operative times mean longer
periods of hypoperfusion to pressure points and
increase the likelihood of ulcer formation [ 6 ].
The most common sites of pressure ulcer formation are the sacrum, heels, ischium, and trochanter, and special attention should be paid to ensure
that these areas are appropriately positioned and
padded for surgery [ 5 ].
To prevent the formation of pressure ulcers
during surgery in the lateral decubitus position, it
is important for the surgeon to make sure that all
dependent areas and boney prominences are
properly padded after positioning. Ideally, the
circulating nurse should also be vigilant during
the procedure to ensure that the patient does not
slip out of position underneath the drapes.
Despite these precautions, if a patient develops
pressure ulcers as a result of surgery, this should
be disclosed to the patient and the wound should
be cared for appropriately. Severe ulcers may
require evaluation by a plastic surgeon.
8.3.2 Peripheral Nerve Injury
Perioperative peripheral nerve injury is
reported to occur after 0.03–0.1 % of surgeries
[ 9 , 18 , 19 ]. Possible mechanisms of peripheral
nerve injury during spine surgery include
direct compression, trauma, ischemia, stretch,
or infl ammatory processes [ 18 ]. Peripheral
8 Positioning and Safety
65
nerve injury may occur when the nerve is
stretched beyond 5–15 % of its resting length
[ 18 , 20 – 22 ]. This in turn increases the intra-
neural pressure and leads to compression of the
vasa nervosum resulting in decreased tissue
perfusion and nerve fi ber ischemia [ 20 ].
Similarly direct nerve compression may also
lead to a reduction in perfusion pressure and
subsequent nerve ischemia thereby slowing
nerve fi ber conduction [ 18 , 23 ]. The most com-
mon site of perioperative peripheral nerve
injury is the ulnar nerve which occurs in 0.5 %
of patients undergoing noncardiac surgery [ 9 ,
24 ]. The ulnar nerve may be more prone to
injury if there is a preexisting subclinical neuropathy. Abnormal nerve conduction has been
observed in the contralateral ulnar nerve in
patients who developed perioperative ulnar
nerve injury [ 25 ]. Furthermore, ulnar nerve
injury is more common in males. This may
occur because men have a statistically larger
coronoid process of the ulna, while women
have increased fat over the medial aspect of the
elbow [ 26 ]. Another common site of peripheral
nerve injury during surgery is the brachial
plexus. Brachial plexus injury more commonly
involves the upper nerve roots [ 18 ]. In the lat-
eral decubitus position, brachial plexus injury
may occur if the axillary roll is place too high
within the axilla itself causing injury due to
direct compression. On the nondependent side
brachial plexus injury may occur if the nondependent arm is hyper- abducted or if the head is
tilted downward. Extreme elbow fl exion or
extension should also be avoided [
18 ].
8.3.3 Rhabdomyolysis
8.3.4 Postoperative Visual Loss
Although postoperative visual loss is generally
associated with patients undergoing spine surgery
in the prone position, this exceedingly rare but
devastating complication has been reported in
patients who are positioned in the lateral decubitus position as well [ 18 , 30 ]. The most common
causes of postoperative visual loss are ischemic
optic neuropathy and central retinal artery occlusion. More specifi cally, posterior ischemic optic
neuropathy is the most likely cause after spine
surgery. The etiology of this condition is unknown;
however, to minimize the risk of this complication, the patient’s eyes should be closed and free
from external pressure during positioning, and the
head should be positioned above the heart in neutral forward position when possible [ 31 ].
Conclusion
Understanding how to properly position a patient
in the lateral decubitus position is crucial for
spine surgeons, especially given the increasing
popularity of minimally invasive surgeries per-
formed in this position. Although patient posi-
tioning is a team effort involving the surgeon,
nursing, and anesthesia, it remains the surgeon’s
responsibility to ensure that the patient is posi-
tioned in a way such that optimizes surgical
exposure while minimizing risk to the patient.
Complications including pressure ulcers, periph-
eral nerve injury, rhabdomyolysis, and perioper-
ative visual loss may occur rarely despite
preventative measures [
is important to identify and treat these complica-
tions early, and patients should be aware of these
potential complications prior to surgery.
9 ]. In these situations, it
There are reports of rhabdomyolysis following
surgery in the lateral decubitus position [ 10 , 27 –
29 ]. This rare complication is associated with
longer operative time, male sex, and increased
body mass index [ 10 , 27 ]. To identify this com-
plication early, the anesthesia provider should
closely monitor urine output and renal function
in obese patients who are undergoing long
surgeries.
References
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J Bone Joint Surg. 1954;36-b(2):173–9.
2. Lu Y, Wong JM, Chi JH. Chapter 172: Lateral lumbar
interbody fusion: indications and techniques. In:
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3. Bergey DL, Villavicencio AT, Goldstein T, Regan
JJ. Endoscopic lateral transpsoas approach to the lumbar spine. Spine. 2004;29(15):1681–8.
4. Ozgur BM, Aryan HE, Pimenta L, Taylor
WR. Extreme Lateral Interbody Fusion (XLIF): a
novel surgical technique for anterior lumbar interbody
fusion. Spine J Off J N Am Spine Soc.
2006;6(4):435–43.
5. St-Arnaud D, Paquin MJ. Safe positioning for neurosurgical patients. AORN J. 2008;87(6):1156–68; quiz
69–72.
6. Bonnaig N, Dailey S, Archdeacon M. Proper patient
positioning and complication prevention in orthopaedic surgery. J Bone Joint Surg Am.
2014;96(13):1135–40.
7. Cheney FW, Domino KB, Caplan RA, Posner
KL. Nerve injury associated with anesthesia: a
closed claims analysis. Anesthesiology. 1999;90(4):
1062–9.
8. Kroll DA, Caplan RA, Posner K, Ward RJ, Cheney
FW. Nerve injury associated with anesthesia.
Anesthesiology. 1990;73(2):202–7.
9. Cassorla LL, Jae-Woo. Chapter 41: Patient positioning and associated risks. In: Miller R, editor. Miller’s
anesthesia. 8th ed. Philadelphia: Saunders; 2015.
10. Akhavan A, Gainsburg DM, Stock JA. Complications
associated with patient positioning in urologic surgery. Urology. 2010;76(6):1309–16.
11. Tuncali BE, Tuncali B, Kuvaki B, Cinar O, Dogan A,
Elar Z. Radial nerve injury after general anaesthesia
in the lateral decubitus position. Anaesthesia.
2005;60(6):602–4.
12. Deane LA, Lee HJ, Box GN, et al. Third place: fl ank
position is associated with higher skin-to-surface
interface pressures in men versus women: implications for laparoscopic renal surgery and the risk of
rhabdomyolysis. J Endourol/Endourol Soc.
2008;22(6):1147–51.
13. Aronovitch SA. Intraoperatively acquired pressure
ulcer prevalence: a national study. J Wound, Ostomy,
Continence Nurs: Off Publ Wound, Ostomy
Continence Nurses Soc/WOCN. 1999;26(3):130–6.
14. Primiano M, Friend M, McClure C, et al. Pressure
ulcer prevalence and risk factors during prolonged
surgical procedures. AORN J. 2011;94(6):555–66.
15. Schoonhoven L, Defl oor T, Grypdonck MH. Incidence
of pressure ulcers due to surgery. J Clin Nurs.
2002;11(4):479–87.
16. Schultz A, Bien M, Dumond K, Brown K, Myers
A. Etiology and incidence of pressure ulcers in surgical patients. AORN J. 1999;70(3):434, 7–40, 43–9.
17. Walton-Geer PS. Prevention of pressure ulcers in the
surgical patient. AORN J. 2009;89(3):538–48; quiz
49–51.
18. Kamel I, Barnette R. Positioning patients for spine
surgery: avoiding uncommon position-related complications. World J Orthop. 2014;5(4):425–43.
19. Welch MB, Brummett CM, Welch TD, et al.
Perioperative peripheral nerve injuries: a retrospective
study of 380,680 cases during a 10-year period
at a single institution. Anesthesiology. 2009;111(3):
490–7.
20. Ogata K, Naito M. Blood fl ow of peripheral nerve
effects of dissection, stretching and compression.
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21. Tanoue M, Yamaga M, Ide J, Takagi K. Acute stretching of peripheral nerves inhibits retrograde axonal
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22. Wall EJ, Massie JB, Kwan MK, Rydevik BL, Myers
RR, Garfi n SR. Experimental stretch neuropathy.
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23. Winfree CJ, Kline DG. Intraoperative positioning
nerve injuries. Surg Neurol. 2005;63(1):5–18;
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24. Warner MA, Warner DO, Matsumoto JY, Harper
CM, Schroeder DR, Maxson PM. Ulnar neuro
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25. Alvine FG, Schurrer ME. Postoperative ulnar-nerve
palsy. Are there predisposing factors? J Bone Joint
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DR. Anatomy of the ulnar nerve at the elbow: potential relationship of acute ulnar neuropathy to gender
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P. Rhabdomyolysis and operating position.
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Intraoperative Electrophysiologic Monitoring
Reid R. Hoshide and William R. Taylor
9
9.1 Introduction
The lateral approach to minimally invasive lumbar spine surgery has been around since the 1980s
[ 1 – 6 ]. However, this approach had been fraught
with resultant nerve injuries which were appreciated postoperatively. In its beginnings, the rate of
intraoperative nerve injury during lateral
approaches to lumbar spine surgery was approximately 30 %, making this approach unappealing
compared to alternative approaches to the lumbar
spine [ 1 ]. The addition and advances of intraop-
erative neuromonitoring (IONM) have made this
technique safer with lesser rates of postsurgical
paresis. Advances in IONM made this previously
morbid approach less morbid by means of awareness to the surrounding neural structures that can
be compromised with the lateral access approach
to the spine. In this chapter, we describe the considerations, benefi ts, and utility of IONM in lateral access lumbar spine surgery.
R. R. Hoshide , MD., MPH.
Department of Neurosurgery , University of
California - San Diego , San Diego , CA 92103 , USA
W. R. Taylor , MD. (*)
Department of Neurosurgery , University of California
at San Diego , La Jolla , USA
wrtaylormd@yahoo.com
e-mail:
9.2 Anatomic Considerations
The lumbar plexus is a network of motor and sensory nerves that start from the L1 nerve root and
end at the L5 nerve root. The lumbar plexus traditionally runs lateral to the dorsal half of the vertebral body. The one exception of this dorsal-half
travel of the lumbar plexus is the genitofemoral
nerve. The genitofemoral nerve emerges from L1
and L2 and runs obliquely within the psoas muscle, running anterior relative to the vertebral bodies. A small cadaveric study revealed that if the
lateral disc space was divided into four zones
from anterior to posterior, zones I, II, and III were
free of major motor nerves in the L3–4 disc
space. The L4–5 disc space was free of major
motor nerves in zones I to II. The genitofemoral
nerve, the nerve most prone to injury, was
observed coursing through the psoas muscle at
zone II at L2–L3, emerging from the psoas at
zone I at L3–4, and superfi cial to the psoas at
L4–5 in zone I [
the genitofemoral nerve makes it vulnerable to
collateral injury when accessing the lateral lumbar spine (Fig. 9.1 ).
Sensory nerves can also be at risk for injury. A
small cadaveric study has shown that the iliohypogastric, ilioinguinal, and the lateral femoral
cutaneous nerves run obliquely during blunt retroperitoneal dissection [ 10 ]. Unfortunately, it is
diffi cult to measure injury to these sensory nerves
during lateral access spine surgery.
7 – 9 ]. This serpentinous course of
© Springer International Publishing Switzerland 2017
M.Y. Wang et al. (eds.), Lateral Access Minimally Invasive Spine Surgery,
DOI 10.1007/978-3-319-28320-3_9
67