Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6011_Библиотеки_им_академика_М_И_Перельмана.pdf
C H A P T E R 5 9 Minimally Invasive Spinal Surgical (MISS) Techniques for the Decompression of Lumbar Spinal Stenosis
F IG UR E 5 9- 11 Interspinous devices. Clockwise from top left: X-Stop,
Diam, Coflex, Wallis.
lus, as well as the facet joints themselves. Accordingly, several groups have
reported benefits for use of interspinous devices in patients with degenerative mechanical pain without stenosis as well.
28
References
1. L. Khoo, R. Fessler, Microendoscopic decompressive laminotomy for the treatment of lumbar stenosis, Neurosurgery 5 (Suppl. 5) (2002) S146–S154.
2. P. Guigui, E. Barre, M. Benoist, A. Deburge, Radiologic and computed tomography image
evaluation of bone regrowth after wide surgical decompression for lumbar stenosis, Spine 24
(1999) 281–289.
3. T.J. Kleeman, A.C. Hiscoe, E.E. Berg, Patient outcomes after minimally destabilizing lumbar
stenosis decompression: the Port-Hole technique, Spine 25 (2000) 865–870.
4. A.C. Simotas, F.J. Dorey, K.K. Hansraj, F. Cammisa, Nonoperative treatment for lumbar spinal stenosis: clinical and outcome results and a 3-year survivorship analysis, Spine 25 (2000)
197–204.
395
5. A. Herno, T. Saari, O. Suomalainen, Airaksinen, The degree of decompressive relief and its
relation to clinical outcome in patients undergoing surgery for lumbar spinal stenosis, Spine
24 (1999) 1010–1014.
6. S.J. Atlas, R.B. Keller, D. Robson, R.A. Deyo, D.E. Singer, Surgical and nonsurgical manage-
ment of lumbar spinal stenosis: four-year outcomes from the Maine Lumbar Spine Study,
Spine 25 (2000) 556–562.
7. H. Hurri, P. Slatis, K. Soini, et al., Lumbar spinal stenosis: assessment of long-term outcome
12 years after operative and conservative management, J. Spin. Dis. 11 (1998) 110–115.
8. J.N. Katz, G. Stucki, S.J. Lipson, et al., Predictors of surgical outcome in degenerative lumbar
spinal stenosis, Spine 21 (1999) 2229–2233.
9. F. Postacchini, Spine update: surgical management of lumbar spinal stenosis, Spine 24
(1999) 1043–1047.
10. L.D. Herron, C. Mangelsdorf, Lumbar stenosis: results of surgical treatment, J. Spinal
Disord. 4 (1991) 26–33.
11. P.L. Sanderson, P.L.R. Wood, Surgery for lumbar spinal stenosis in old people, J. Bone Joint
Surg. Br. 75 (1993) 393–397.
12. R .Y.C. Tsai, R.S. Yang, R.S. Bray, Microscopic laminotomies for degenerative lumbar spinal
stenosis, J. Spin. Dis. 11 (1998) 389–394.
13. G.F. Tuite, J.D. Stern, S.E. Doran, et al., Outcome after laminectomy for lumbar spinal stenosis, part I: clinical correlations, J. Neurosurg. 81 (1994) 699–706.
14. D.H. See, G.H. Kraft, Electromyography in paraspinal muscles following surgery for root
compression, Arch. Phys. Med. Rehab. 56 (1975) 80–83.
15. T. Sihvonen, A. Herno, L. Paljarva, et al., Local denervation atrophy of paraspinal muscles in
postoperative failed back syndrome, Spine 18 (1993) 575–581.
16. S. Atlas, B. Keller, Y. Wu, R. Deyo, D. Singer, Long-term outcomes of surgical and nonsurgical management of lumbar spinal stenosis: 8-10 year results from the Maine Lumbar Spine
Study, Spine 30 (2005) 936–943.
17. A. Caputy, A. Luessenhop, Long-term evaluation of decompressive surgery for degenerative
lumbar stenosis, J. Neurosurg. 77 (1992) 669–676.
18. J. Katz, S. Lipson, R. Lew, et al., Lumbar laminectomy alone or with instrumented or noninstrumented arthrodesis in degenerative lumbar spinal stenosis. Patient selection, costs, and
surgical outcomes, Spine 22 (1997) 1123–1131.
19. D. Resnick, T. Choudhri, A. Dailey, et al., Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 9: fusion in patients with stenosis and
spondylolisthesis, J. Neurosurg. Spine 2 (2005) 679–685.
20. J. Aryanpur, T. Ducker, Multilevel lumbar laminotomies: an alternative to laminectomy in the
treatment of lumbar stenosis, Neurosurgery 26 (1990) 429–433.
21. J.A. McCulloch, Microsurgical spinal laminotomies, in: J.W. Frymoyer (Ed.), The adult
spine: principles and practice, Raven Press, Ltd., New York, 1991.
22. S. Young, R. Veerapen, S.A. O’Laire, Relief of lumbar canal stenosis using multilevel subarticular fenestrations as an alternative to wide laminectomy: preliminary report, Neurosurgery
23 (5) (1988) 628–633.
23. J.A. Turner, M. Ersek, L. Herron, J. Haselkorn, R. Deyo, Surgery for lumbar spinal stenosis,
attempted meta-analysis of the literature, Spine 17 (1992) 1–8.
24. B.H. Guiot, L.T. Khoo, R.G. Fessler, A Minimally invasive technique for decompression of
the lumbar spine, Spine 27 (4) (2002) 432–438.
25. S. Palmer, R. Turner, R. Palmer, Bilateral decompression of lumbar stenosis involving a unilateral approach with microscope and tubular retractor system, J. Neurosurg. Spine 97 (2002)
213–217.
26. R . McCaffert, L. Khoo, M. Perez-Cruet, Percutaneous pedicle screw fixation of the lumbar
spine using the pathfinder system, in: M. Perez-Cruet, L. Khoo, R. Fessler (Eds.), An anatomic approach to minimally invasive spine surgery, QMP, St. Louis, 2006, pp. 599–614.
27. J.F. Zucherman, K.Y. Hsu, C.A. Hartjen, et al., A multicenter, prospective, randomized
trial evaluating the X STOP interspinous process decompression system for the treatment
of neurogenic intermittent claudication: two-year follow-up results, Spine 30 (12) (2005)
1351–1358.
28. J. Senegas, Mechanical supplementation by non-rigid fixation in degenerative intervertebral
lumbar segments: the Wallis system, Eur. Spine J. 11 (2) (2002) S164–S169.
Minimally Invasive Scoliosis Treatment
Choll W. Kim, Kamshad Raiszadeh, and Steven R. Garfin
60
k e y p o i n t s
Minimally invasive spine (MIS) techniques for the treatment of scoliosis are
relatively new.
e direct lateral interbody fusion technique is a powerful method of
deformity correction.
Percutaneous pedicle screw fixation can be performed from T10 to the pelvis.
Stenosis can be treated without laminectomy via indirect decompression.
Endoscopic transforaminal decompression is a promising technique for
treating radiculopathy due to neuroforaminal stenosis at the concavity of the
scoliotic segment.
INTRODUCTION
The degenerative cascade can occur in a variety of ways. When the disc
degenerates and loses its height, shortening of the anterior spinal column
occurs. In most cases, the collapse of the disc space occurs symmetrically,
leading to loss of lumbar lordosis and accentuation of thoracic kyphosis.
However, the disc may collapse asymmetrically, which in turn can lead to
a lateral bending of the spine. When this occurs over multiple segments, a
degenerative scoliosis may develop, causing imbalance in posture, often in
both the coronal and the sagittal planes.
The anatomic characteristics of degenerative scoliosis and idiopathic
adolescent scoliosis differ significantly. Whereas scoliosis that develops in
childhood is marked by significant rotation of the vertebral bodies, little
rotation is appreciated in most adult degenerative scoliosis patterns. Furthermore, there is a propensity for the adult scoliosis curve to develop in
the lumbar rather than the thoracic spine. This is likely due to the greater
mobility of the lumbar spine, which undergoes a more clinically evident
degeneration of the disc.
The treatment of scoliosis in the aging spine differs markedly from scoliosis treatment of the growing spine. The key differences are the lack of mobility
of the adult spine, the presence of osteopenia and osteoporosis, the location
of the curve, the curve magnitude, the need for decompression, and the frailty
of older patients with their associated comorbidities. The goals of treatment
differ as well. In adolescent idiopathic scoliosis, there is more concern with
deformity and less with pain. In adult degenerative scoliosis symptoms are
related more to pain (both back pain and nerve pain) than deformity.
As our population increases in age, the prevalence of symptomatic
degenerative scoliosis will increase concomitantly. The incidence of complications is high for this type of surgery.
increases with advanced age and other medical comorbidities. The goal of
minimally invasive surgery is to decrease the soft tissue trauma associated
with large midline posterior and thoracoabdominal approaches, which
require take-down of the diaphragm. This chapter addresses the key indications for surgical treatment, minimally invasive strategies for scoliosis treatment, contraindications to minimally invasive surgery, and potential pitfalls
of MIS treatment.
1
2
The risk of these complications
396
BASIC SCIENCE OF MINIMALLY INVASIVE SPINE SURGERY
The posterior paraspinal muscles provide dynamic stability to the spinal
3
column.
Numerous studies have investigated the anatomic, histologic, and
radiographic properties of many of these muscles with the goal of understanding pathologic changes associated with spinal abnormalities such as
chronic low back pain, disc herniation, scoliosis, and degenerative lumbar
kyphosis. Paradoxically, some operations designed to treat these various
spinal disorders actually disrupt these muscles and, in turn, may lead to
substantial functional deficits, various pain syndromes, or both. Minimally
invasive spine surgery techniques strive to minimize surgical trauma to
these muscles, thereby preserving their function. Architectural studies show
that the multifidus muscle stands out among all other lumbar muscles, and
indeed many extremity muscles, as a most extreme example of a muscle
designed to stabilize the lumbar spine against flexion. This functional design
was elucidated by means of intraoperative laser diffraction and quantitative architecture measurements that demonstrated (1) an extremely large
physiologic cross-sectional area, greater than that of any other lumbar spine
muscle, and (2) a sarcomere length range exclusively on the ascending portion of the length–tension curve.
and relatively short fibers indicate that the multifidus muscle is architecturally designed to produce large forces over a narrow range of lengths. This
design allows the multifidus muscle to function more to stabilize the spine
and less to provide motion of the spine. As a stabilizer, it acts to maintain
optimal joint forces throughout the spine as the body assumes various positions requiring prolonged flexion (such as assembly-line work) or extension
(such as standing).
4
The large physiologic cross-sectional area
CLINICAL PRACTICE GUIDELINES
The main reason for surgical treatment of adults with scoliosis is pain. Pain
can occur in several ways. First, the pain of neurogenic claudication develops
with the degenerative cascade. This is exacerbated by spinal malalignment.
Both lateral listhesis and anterolisthesis reduce the area of the canal. The
resulting stenosis is more severe than the corresponding degree of degeneration in a well-aligned spine. If there is severe asymmetric disc collapse, the
neuroforamina will close down on the side of the concavity, which in turn
can cause radiculopathy.
Pain also occurs because of the degenerative arthritis that develops
within the disc and facet joints. Bone-on-bone movement between motion
segments can cause pain in a manner analogous to degenerative joint disease
in the knee and hip. Furthermore, a malalignment will create focal areas
of increased stress. Finally, postural imbalance can lead to fatigue-related
muscle pain. Much as in flat back syndrome, early muscle fatigue and pain
can develop as the patient tries to compensate for coronal and/or sagittal
imbalance. In contrast to adolescent scoliosis, the concern for curve progression is relatively low. The pain associated with stenosis, radiculopathy, and
early muscle fatigue drives surgical decision-making. It is rare to perform
surgical correction of deformity in the absence of pain in adults with degenerative scoliosis.
C H A P T E R 6 0 Minimally Invasive Scoliosis Treatment
397
Endoscopic Transforaminal Decompression for Unilateral Radiculopathy
Occasionally, a patient with degenerative scoliosis will complain mainly of
leg pain, with only minor back pain. In most cases, the pain is due to neuroforaminal stenosis. Traditionally, this has been treated with hemilaminectomy and foraminotomy. However, there is risk of worsening deformity
A
B
due to loss of stability when excessive bony resection is necessary and
when the activity of the multifidus muscle is disrupted. An extraforaminal
approach has been used with good success via a Wiltse-type paramedian
approach. A minimally invasive modification of this technique utilizes
tubular retractors that dilate the soft tissue and minimize retraction pressures. Although this is still performed with the patient under general
anesthesia, the accessibility of the neuroforamen is sufficient. However, it
C
D
E
G
F IG UR E 6 0- 1 Endoscopic Transforaminal Decompression. A 7-mm endoscopic cannula is placed at the extraforaminal opening of the affected level. A
combination of bipolar probes (Ellman International, Inc., Oceanside, N.Y.), holmium side-firing lasers (Trimedyne, Inc., Irvine, Calif.), and mechanical trephines
(Joimax, Inc., Campbell, Calif. ) are used to release the neuroforaminal ligament, superior edge of the facet joint capsule, and lateral edge of the ligamentum flavum as it becomes confluent with the facet joint capsule. Mechani cal trephines are used under fluoroscopic guidance to remove the superior edge of the superior
articular process. A combination of ligamentous release with a small a mount of bony resection decompresses the exiting nerve root. The angled bipolar probe is
passed into the spinal canal to manually confirm adequate decompression. A, AP radiograph showing asymmetric disc collapse with narrowing of the left L4 and
L5 neurofor amina. B, Left parasagittal T1-weighted MR image showing narrowing of the left L4 and L5 neuroforamina. (open arrows) C, Endoscopic view of the
facet joint capsule. D, Endoscopic view of the semicircular removal of superior articular process using trephines. The rough cancellous bone can be seen as a superior
dome in the field of view. E, Intraoperative AP C-arm image showing the endoscopic cannula docked at the extraforaminal openin g of the left L4 neuroforamen.
F, Intraoperative lateral C-arm image showing the endoscopic cannula docked at the extraforaminal opening of the left L4 neuroforamen. Intraoperative AP image
showing the endoscopic angled probe pass ing through the superior (G), middle (H), and inferior (I) aspects of the neuroforamen. The ability to pass the probe
through the neuroforamen wit hout resistance confirms an adequate decompression.
H
F
I
398
P A R T V I I Surgical Treatment Modalities: Lumbar Spine
is technically challenging to use the operating microscope because of the
angle of the approach.
The endoscopic technique provides another avenue of treatment and
it can be performed using local anesthesia.
5
This is advantageous for
patients with significant medical comorbidities that make general anesthesia risky. Furthermore, the endoscopic technique allows a more lateral
trajectory to the spine, facilitating deeper entry into the neuroforamen
(Figure 60-1).
Deformity Correction via Direct Lateral Anterior Interbody Fusion
A powerful method of deformity correction is the direct lateral inter-
body fusion (DLIF) technique (Figures 60-2 through 60-5). This technique was best described by Ozgur and colleagues
system (Nuvasive, San Diego, Calif.). The key feature of the technique
is the ability to rest the interbody spacer along the strongest portion of
the vertebra endplate, namely, the cortical rim or apophyseal ring. The
6
using the XLIF
annulus inserts at this location and the cortex of the vertebral body
acts as a vertical support. Because the interbody spacer is placed from
the lateral position, the implant may overhang past the edge of the disc
space, ensuring that the implant fully rests on the strongest portion of
the endplate. If placed from an anterior or anterolateral position, the
interbody spacer would enter the canal or the neuroforamen. In addition,
the DLIF technique preserves the anterior longitudinal ligament. It is
presumed that by keeping the integrity of this structure, the spine maintains a pivot point from which to correct an asymmetrically collapsed
disc.
A comparison of interbody fusion techniques shows that the direct
lateral interbody technique allows for greater deformity correction than
anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody
fusion (TLIF) or posterolateral fusion without interbody fusion. A radiographic comparison of various treatment groups showed that the focal Cobb
angle for DLIF was two to four times that for the other treatment methods
(Figure 60-6). The main drawback of this technique is approach-related
nerve root irritation, which occurs in 3.4% of patients.
7
A
O
B
F IG UR E 6 0 -2 Lateral Positioning for Direct Lateral Interbody Fusion (DLIF). An important step in the safe application of the DLIF procedure is proper patient
positioning. The patient is placed on a breaking rad iolucent table. A soft support is placed at the lat eral hip at the level o f the iliac crest (A). Th e break in the table
is placed at the same area (black oval). The patient is secured to the table using sticky rolls or a moldable beanbag device. Soft tape is placed at the hips (over
the greater trochanters) and just below the shoulders. The hips and knees are flexed in a comfortable position at about 45 degrees. Transverse pill ows are placed
between the legs. A strap is then gently placed above the ankles to maintain this pos ition. The patient must be adequately secured to the table so that the table
itself can be rotated (“airplaned”), ensuring that the surgical target site is perfectly lateral relative to the floor. This is best accomplished by using the C-arm under
the table flat to the floor. The table is then rolled until a perfect AP image is obtained (B). In most cases of degenerat ive scoliosis, there is some mild rotation such
that the caudal vertebral body and the cephalic vertebral body cannot be in a perfect AP position simultaneously. In this instance, the caudal vertebral body is usually
used as the reference level. This process is required at each level to adjust for rotational deformities between levels. The lateral image is used to target the midportion of the disc space (C). At L4-5, the nerve root can be at this position. In such cases, the initial dilator is targeted more anteriorly and thereafter pulled posteriorly
to the disc midpoint. This allows the dilator to enter the psoas muscle anterior to the nerve root and by sweeping posteriorly creates a cuff of muscle that separates
the dilator from the nerve root. The iliac crest can impede access to the L4- 5 disc space (dotted lines). It is important to ascerta in before surgery that iliac crest can
be pulled out of the way by lateral bending of the patient on the operating table, as descri bed in A.
C
C H A P T E R 6 0 Minimally Invasive Scoliosis Treatment
399
A
Ao
V.C
SAFE ZONE
N.R
N.
R
B
Vertebral AP diameter
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Lateral access safe zone
42.7% 44.0%
47.9%
L1–2 L2–3 L3–4 L4–5
Vertebral level
13.1%
C
RV/VTB
Safe zone
D
F IG UR E 60 -3 Direct Lateral Retroperitoneal Transpsoas Approach. The skin incision is made with the aid of the C-arm in the direct lateral position.
Gentle blunt dissection is accomplished with angled Mayo scissors. The muscles of the lateral abdominal wall are entered between muscle fib ers (A). Numerous sensory ner ves are encountered, which can be swept out of the surgical corridor. The retroperitoneal space is entered by cautious, gentle spreading of
the tranversus abdominis fascia, which can be thick in younger patients. Finger dissection is then used to open the potential space of the retroperitoneum.
Upon entering the retroperitoneal space, the finger is immediately directed poster iorly to the inner abdominal wall as shown by the dotted lines (B). A backand-fort h motion is u sed to release thin reticular attachments of the re troperitoneal fat to the abdominal wall. The tip of the traverse process is used as the
initial landmark. At L4-L5, the iliolumbar ligament is palpated as well as the anterior as pect of the iliacus muscle. Blunt finger dissection is further taken
anterior ly o ver the psoa s muscle, wh ich is very soft and delicate to the touch. Care should be taken to avoid undue maceration of the fragile muscle fibers.
The initial dil ator is then passed down along the finger and docked gently on the surface of the psoas muscle. The initial dil ator is kept in contact with the
finger to facilitate safe passage of the tip through the retroperitoneal space and ensure that it does not capture any abdominal structures such as bowel
or ureter. Using the C-arm, the tip of the initial dilator is positioned at the di sc cente r and the psoas muscle entered gently using a back-and-forth twisting
motion. Because the psoas muscle is soft it will not cause res istance. Neurophysiologic monitoring via free-run and triggered EMG is used to confirm that the
nerve root is not in the path of the initial dilator. The safe zone for the tra nspsoas approach is anterior to the nerve root and posterior to the vena ca va (C).
The limi ts of this safe zone suddenly narrow at L4-L5 compared to the more cephalic levels (D).
NR/VTB
400
P A R T V I I Surgical Treatment Modalities: Lumbar Spine
A
C
B
D
E
F IG UR E 6 0 -4 Disc Exposure. Once the initial dilator is safely passed through the psoas muscle and positioned on the disc space, a guidewire is inserted
into the disc to hold the dilators in place. Serial dilation is then performed with larger tubular rings. At each step, neurophysiologic monitoring is used to avoid the
nerve root. After the final dilator, an expandable tubular retractor (A and B) is slid down using a back-and-forth motion (Medtronic Spine, Memphis, Tenn.). Thin
fibers of the psoas are often found over the disc space (C). These fibers should be only 1 to 2 mm thick and can be swept aside with the suction tip or a Penfield
4 probe. The blades of the retractor contain slots for bone fixation screws (white arrow, C) that can be used to pass the neuromonitoring probe (NIM, Medtronic,
Memphis, Tenn.) down to the bone surface (white arrow, D). The bone fixation screw is inserted through the slots in the retractor (E). It is best to position the bone
screw immediately adjacent to the disc space (F). Before insertion of the bone screw, the ball-tip neuromonitoring probe (open arrow, F) is used to ensure that the
bony surface is free of neural structures.
F
A
B
C
E
D
F
G
F IG UR E 6 0- 5 Direct Lateral Discectomy. A key component of the DLIF discectomy is release of the contralateral annulus. This can be accomplished with a
Cobb-type periosteal elevator (A). Using a mallet, the elevator is gently tapped until it penetrates the annulus. A palpable release can be appreciated. Although the
tip of the elevator may protrude up to 1 cm past the lateral vertebral body line, no known clinical sequelae have been observed. Once a subtotal discectomy, endplate
preparation, and contralateral annular release have been accomplished, smooth trials are used to dilate the disc space (B to D). The interbody device of the appropriate size is then tamped into place. Using a wide interbody spacer that rests on the lateral cortical rim of the vertebral body, a dramatic reduction and disc height
restoration can be seen (E to G). The specialized retractor provides an optimal view of the surgical corridor before (D) and after insertion (H) of the interbody spacer.
H
402
Reduction in Focal Cobb Angle
P A R T V I I Surgical Treatment Modalities: Lumbar Spine
(per fusion level)
48%
41
4 60 2
66%
60 8020 400
F IG UR E 60 -6 Deformity Correction using the DLIF Technique. A retrospective radio-
graphic review comparing various fusion techniques shows the superiority of the DLIF technique
for reduction of focal Cobb angle in patients with degenerative scoliosis (A) and reduction of
spondylolisthesis (B).
DLIF (n 117)
ALIF (n 22)
TLIF (n 19)
PLIF (n 47)
A
Percent Reduction in Spondylolisthesis
XLIF/DLIF (n 20)
MIS TLIF (n 27)
B
1.4
1.4
1.2
Degrees of correction
Percent
Minimally Invasive Posterior-Only Approaches
The most common minimally invasive posterior approach is the minimally
invasive transforaminal lumbar interbody fusion (MIS TLIF). Utilizing a
paramedian approach, a unilateral facetectomy may be performed on the
side requiring maximum correction.
8
Interbody fusion allows for a high
fusion rate and provides additional soft tissue release needed for deformity
correction. The MIS TLIF strategy is particularly attractive if there is a
large disc herniation, facet cyst, and/or severe stenosis requiring a direct
decompression.
A key limitation is the difficulty in placing a sufficiently large interbody spacer to restore disc space height. Additionally, each level requires
a separate and distinct dissection. In cases in which there are more than
three levels to be corrected, this technique can be time-consuming and
laborious.
Percutaneous Pedicle Screw Fixation
Multilevel fixation with pedicle screws and rods remains one of the most
significant challenges in the minimally invasive treatment of degenerative
scoliosis. In contrast to open techniques, the percutaneous rods cannot be
reduced into the tulip of the pedicle screws, nor can a rotation maneuver
be performed. The method of bringing the rod to the screw relies on screw
extension sleeves that serve to guide the rods through each tulip and thereafter reduces the rod into the seat of the tulip so that a fixation nut can
be applied (Figure 60-7). The greatest challenge occurs at the lumbosacral junction, where there is a sudden curvature due to the lordotic angle
between L4 and S1 (See Figure 60-7H). Extreme care must be exercised
to align the height of the tulips. With osteoporotic bone, misalignment
can lead to screw pullout during the reduction maneuver. The use of bone
cement injected into the pedicles immediately before screw insertion greatly
improves fixation strength.
9
MIS Iliac Fixation
The use of iliac screws improves fusion rates at L5-S1 when the construct is
long. An important technique in posterior deformity correction is insertion
of iliac screws in a minimally invasive fashion.
point of the iliac screws on the medial wall of the posterior superior iliac
spine (PSIS) about 2 cm distal to the S1 screw, the tulips of the screws can
be aligned so that a rod can be passed through both the S1 screw tulip and
the iliac screw tulip (Figure 60-8). Meticulous attention to rod contouring is
required to ensure that the construct is not under undue stress.
10
By placing the insertion
A
B
C
E
D
F
G
F IG UR E 6 0- 7 MIS Pedicle Screw Fixation. Meticulous intraoperative AP (A) and lateral (B) imaging is required to enter the pedicle using percutaneous or
mini-open techniques. A sleeve to guide rod insertion is required to facilitate passage of the rod over multiple levels (C, E). The design of the sleeve should provide a
relatively large opening to simplify rod insertion and reduction of the rod down to the tulip of the pedicle screw (D, F). The depth of screw insertion should be monitored carefully using lateral C-arm imaging to avoid step-offs, which make rod reduction difficult (G). Careful rod contouring is also necessary, particularly if crossing
the lumbosacral junction, where there is a sudden increase in lordosis (H). Pelvic fixation can be accomplished through a small surgical corridor that is immediately
adjacent to the L5-S1 exposure (MIS pelvic screw marked by * in H).
H
404
P A R T V I I Surgical Treatment Modalities: Lumbar Spine
Case Studies
Minimally invasive scoliosis surgery relies on three main technologies:
(1) DLIF/XLIF, (2) posterior MIS TLIF, and (3) percutaneous pedicle screw instrumentation. Using a combination of these techniques,
deformities of the thoracolumbar spine spanning T10 to the pelvis can
be treated. e most common and most straightforward problem is a
degenerative scoliosis from L2 to L5 with back pain and neurogenic
claudication (Figure 60-8). Using a lateral interbody approach, much
of the stenosis can be addressed by correcting the Cobb angle and reestablishing the disc space height. In doing so, an indirect decompression can be achieved in some cases without the need for a posterior
laminectomy.
A
Before
B
After
E
F IG UR E 6 0 -8 Case 1: L2-L5 Degenerative Scoliosis with Stenosis. Standing AP (A) and lateral (C) radiographs of a 72-year-old man with constant back pain
and neurogenic claudication. Patient avoided surgical treatment because of fear of intraoperative risks of traditional open surgery. Current medical problems include
hypertension and mild chronic obstructive pulmonary disease. Patient underwent angioplasty 2 years ago. Surgical treatment was performed in 1 day via stage 1
direct lateral anterior interbody fusion at L2-L3, L3-L4 and L4-L5. Estimated blood loss was 50 ml, and surgical time was 127 min. The patient was repositioned and
nonsegmental posterior instrumentation was performed through 18-mm percutaneous incisions. The rod was inserted through proximal stab incisions (F, blue arrow).
The navigation patient reference frame was placed percutaneously on the left posterior superior iliac spine (F, white arrow). Decompression was achieved indirectly via
deformity correction and disc space height restoration. No laminectomy was performed. Patient was ambulating on postoperative day 1 with resolution of leg pain.
He was discharged on postoperative day 3. At 1-year postsurgery, his visual analog scale is 2-3 and his walking tolerance is 2 miles.
C
Before
L2
F
D
After
L5