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_6033_Библиотеки_им_академика_М_И_Перельмана.pdf
238
evidenced by low stimulation thresholds with the
dilators. In these instances, the lumbar plexus is
swept posteriorly. Rarely, the plexus cannot be
avoided and the procedure must be aborted. A metaanalysis of lumbar plexopathies following the lateral approach found that reporting of plexus injuries
in the literature has been inconsistent with the incidence of motor weakness ranging from 0.7 to
33.6 % [ 30 ]. There was a lack of consistency in the
descriptions of lumbar plexopathies and a lack of
diagnostic paradigms. The true incidence of plexus
injury is unknown, and evolving techniques have
likely diminished the incidence over time [ 31 ].
Dissecting through the psoas muscle can also
lead to transient weakness in hip fl exion and
anterior thigh pain/numbness from tension on the
genitofemoral nerve which lies on the surface of
the psoas muscle [ 25 ]. Anatomic variants, which
place the vasculature lateral relative to the vertebral body, should be excluded from the lateral
approach if there is not enough room to safely
perform the diskectomy and place a cage.
Finally, this technique relies upon an indirect decompression to relieve any neurological
symptoms. Though rare, patients whose neurological symptoms are not relieved will still
require a posterior decompression.
M.F. Gary and M.Y. Wang
The lateral approach for adjacent segment pathology utilizes the same techniques described previously since the reoperation is across virgin tissue.
Cages allowing for concomitant lateral screw
placement must be carefully planned to avoid the
adjacent screws. Supplementation with posterior
instrumentation requires an open technique to
attach on to the previous hardware. Wang et al.
reported 21 consecutive cases of adjacent segment disease treated with a minimally invasive
lateral interbody fusion without posterior instrumentation [ 27 ]. All of these patients had good
fusion at last follow-up (Fig. 24.3 ).
Those patients with signifi cant proximal junctional kyphosis require a more aggressively lordotic cage for restoring sagittal balance. By
placing the retractor at the midpoint of the disk
space, the soft tissue can be dissected anteriorly
to expose the anterior longitudinal ligament
(ALL). The ALL can then be opened which
allows for placement of a hyperlordotic cage to
correct positive sagittal balance [ 18 , 19 ]. Then
these patients are supplemented with posterior
instrumentation and facetectomies; substantial
sagittal restoration can be achieved.
ab
height and arthrodesis
24 Adjacent Level Disease and Proximal Junctional Kyphosis
proper wound healing and to evaluate on plain
A thorough understanding of the risks unique to
this approach and the best methods of complication avoidance are critical. The lateral approach
requires entrance into the retroperitoneal space.
As such, injury to the bowel is avoided by guiding the instruments to the disk space utilizing
radiography that the alignment is stable. At the
3-month follow-up, dynamic radiographs or a
CAT scan are obtained to ensure proper fusion
has occurred. After the 6-month follow-up, the
patient is usually followed as needed if symptoms have resolved.
the two-fi nger technique to sweep away the
abdominal contents as the dilators are directed
to the disk space. Bowel injury can also be
avoided by utilizing a mini-open technique for
direct visualization of the peritoneum as the
dilators are inserted.
Vascular injury can be avoided by carefully
cavity can also be entered. This engenders the risk
of a pneumothorax. If the parietal pleura is
encountered, care and attention must be taken to
avoid a tension pneumothorax. The pleura can be
stitched and repaired or a small chest tube inserted
and managed in a very conservative manner.
examining the relation of the vasculature to the
disk space and psoas muscle on preoperative
imaging. If there is not enough space to place a
cage with a width of 18 mm, then the lateral
approach is not an option. Also, entering on the
left side is preferred if possible since it avoids the
inferior vena cava, which is more vulnerable to
injury and harder to repair than the aorta.
Recognizing segmental branches and ligating
them prior to incising the disk is critical to avoiding excessive blood loss.
The lumbar plexus is more posterior in the
rostral lumbar spine. Since reoperation for adjacent segment disease is typically performed at the
more rostral lumbar levels, injury to the plexus is
much less likely. Techniques to even further
lower this risk include shallow docking and an
oblique lateral approach, which are discussed
1. Cheh G, Bridwell KH, Lenke LG, Buchowski JM,
further in other chapters. Shallow docking can
also be utilized, but frequently the psoas muscle
is very thin at the upper lumbar regions.
2. Lawrence BD, Wang J, Arnold PM, Hermsmeyer J,
Patients are generally sent home from the
hospital in 1–3 days to ensure they can inde-
3. Lee JC, Kim Y, Soh J-W, Shin B-J. Risk fac-
pendently ambulate, void, eat, and pass fl atus.
In general, patients are placed in an external
orthosis for up to 12 weeks, especially when
there is no posterior supplementation. Strenuous
activity and heavy lifting is avoided until fusion
4. Okuda S, Iwasaki M, Miyauchi A, Aono H, Morita
is documented.
239
The fi rst follow-up visit at 6 weeks is to ensure
At the level of T12/L1 or L1/L2, the thoracic
Conclusions
There is a paucity of literature specifi cally
evaluating the lateral interbody technique for
adjacent segment disease. However, the benefi ts afforded by this technique, shorter length,
reduced blood loss, lower CSF leak rate, and
restoration of sagittal balance, are empirically
very promising. Prospective studies evaluating the lateral approach versus posterior revision surgery for adjacent segment disease are
needed to better delineate the benefi ts of this
approach.
Daubs MD, Kim Y, Baldus C. Adjacent segment
disease following lumbar/thoracolumbar fusion with
pedicle screw instrumentation: a minimum 5-year
follow-up. Spine. 2007;32(20):2253–7. doi:
BRS.0b013e31814b2d8e
Norvell DC, Brodke DS. Predicting the risk of adjacent segment pathology after lumbar fusion: a systematic review. Spine. 2012;37(22 Suppl):S123–32.
10.1097/BRS.0b013e31826d60d8 .
doi:
tors of adjacent segment disease requiring surgery after lumbar spinal fusion: comparison of
posterior lumbar interbody fusion and posterolateral
fusion. Spine. 2014;39(5):E339–45. doi:
BRS.0000000000000164
M, Yamamoto T. Risk factors for adjacent segment
degeneration after PLIF. Spine. 2004;29(14):1535–40.
.
.
10.1097/
10.1097/
240
M.F. Gary and M.Y. Wang
5. Park P, Garton HJ, Gala VC, Hoff JT, McGillicuddy JE.
Adjacent segment disease after lumbar or lumbosacral fusion: review of the literature. Spine.
2004;29(17):1938–44.
6. Radcliff K, Curry P, Hilibrand A, Kepler C, Lurie
J, Zhao W, Albert TJ, Weinstein J. Risk for adjacent segment and same segment reoperation after
surgery for lumbar stenosis: a subgroup analysis of the Spine Patient Outcomes Research Trial
(SPORT). Spine. 2013;38(7):531–9. doi:
BRS.0b013e31827c99f0
7. Adogwa O, Owens R, Karikari I, Agarwal V,
Gottfried ON, Bagley CA, Isaacs RE, Cheng
JS. Revision lumbar surgery in elderly patients with
symptomatic pseudarthrosis, adjacent-segment disease, or same- level recurrent stenosis. Part 2. A costeffectiveness analysis: clinical article. J Neurosurg
Spine. 2013;18(2):147–53. doi:
SPINE12226
8. Ekman P, Möller H, Shalabi A, Yu YX, Hedlund
R. A prospective randomised study on the long-term
effect of lumbar fusion on adjacent disc degeneration. Eur Spine J. 2009;18(8):1175–86. doi:
s00586-009-0947-3
9. Helgeson MD, Bevevino AJ, Hilibrand AS. Update on
the evidence for adjacent segment degeneration and
disease. Spine J. 2013;13(3):342–51. doi:
spinee.2012.12.009
10. Lee CK. Accelerated degeneration of the segment
adjacent to a lumbar fusion. Spine. 1988;13(3):375–7.
11. Levin DA, Hale JJ, Bendo JA. Adjacent seg-
ment degeneration following spinal fusion for
degenerative disc disease. Bull NYU Hosp Jt Dis.
2007;65(1):29–36.
12. Radcliff KE, Kepler CK, Jakoi A, Sidhu GS, Rihn J,
Vaccaro AR, Albert TJ, Hilibrand AS. Adjacent segment disease in the lumbar spine following different
treatment interventions. Spine J. 2013;13(10):1339–
49. doi:
13. Schulte TL, Leistra F, Bullmann V, Osada N, Vieth
V, Marquardt B, Lerner T, Liljenqvist U, Hackenberg
L. Disc height reduction in adjacent segments
and clinical outcome 10 years after lumbar 360
degrees fusion. Eur Spine J. 2007;16(12):2152–8.
10.1007/s00586-007-0515-7 .
doi:
14. Chou D, Dekutoski M, Hermsmeyer J, Norvell
DC. The treatment of lumbar adjacent segment
pathology after a previous lumbar surgery: a systematic review. Spine. 2012;37(22 Suppl):S180–8.
10.1097/BRS.0b013e31826d613d .
doi:
15. Miwa T, Sakaura H, Yamashita T, Suzuki S, Ohwada
T. Surgical outcomes of additional posterior lumbar interbody fusion for adjacent segment disease
after single-level posterior lumbar interbody fusion.
Eur Spine J. 2013;22(12):2864–8. doi:
s00586-013-2863-9
16. Whitecloud TS, Davis JM, Olive PM. Operative treat-
ment of the degenerated segment adjacent to a lumbar
fusion. Spine. 1994;19(5):531–6.
.
10.1016/j.spinee.2013.03.020 .
.
.
.
.
10.1097/
10.3171/2012.11.
10.1007/
10.1016/j.
10.1007/
17. Eichholz KM, Ryken TC. Complications of revision
spinal surgery. Neurosurg Focus. 2003;15(3):E1.
18. Isaacs RE, Hyde J, Goodrich JA, Rodgers WB,
Phillips FM. A prospective, nonrandomized, multicenter evaluation of extreme lateral interbody
fusion for the treatment of adult degenerative scoliosis: perioperative outcomes and complications.
Spine. 2010;35(26 Suppl):S322–30. doi:
BRS.0b013e3182022e04
19. Akbarnia BA, Mundis GM, Moazzaz P, Kabirian N,
Bagheri R, Eastlack RK, Pawelek JB. Anterior column realignment (ACR) for focal kyphotic spinal
deformity using a lateral transpsoas approach and
ALL release. J Spinal Disord Tech. 2014;27(1):29–
10.1097/BSD.0b013e318287bdc1 .
39. doi:
20. Castellvi AE, Nienke TW, Marulanda GA, Murtagh
RD, Santoni BG. Indirect decompression of lumbar
stenosis with transpsoas interbody cages and percutaneous posterior instrumentation. Clin Orthop
Relat Res. 2014;472(6):1784–91. doi:
s11999-014-3464-6
21. Dakwar E, Cardona RF, Smith DA, Uribe JS. Early
outcomes and safety of the minimally invasive, lateral
retroperitoneal transpsoas approach for adult degenerative scoliosis. Neurosurg Focus. 2010;28(3):E8.
10.3171/2010.1.FOCUS09282 .
doi:
22. Kepler CK, Sharma AK, Huang RC, Meredith DS,
Girardi FP, Cammisa FP, Sama AA. Indirect foraminal decompression after lateral transpsoas interbody
fusion. J Neurosurg Spine. 2012;16(4):329–33. doi:
0.3171/2012.1.SPINE11528
23. Kotwal S, Kawaguchi S, Lebl D, Hughes A, Huang
R, Sama A, Cammisa F, Girardi F. Minimally invasive lateral lumbar interbody fusion: clinical and
radiographic outcome at a minimum 2-year follow-up. J Spinal Disord Tech. 2015;28(4):119–25.
10.1097/BSD.0b013e3182706ce7 .
doi:
24. Malham GM, Ellis NJ, Parker RM, Seex KA. Clinical
outcome and fusion rates after the fi rst 30 extreme
lateral interbody fusions. Scientifi cWorldJournal.
2012;2012:246989. doi:
25. Moller DJ, Slimack NP, Acosta FL, Koski TR,
Fessler RG, Liu JC. Minimally invasive lateral lumbar interbody fusion and transpsoas approach-related
morbidity. Neurosurg Focus. 2011;31(4):E4. doi:
171/2011.7.FOCUS11137
26. Rodgers WB, Gerber EJ, Rodgers JA. Lumbar fusion
in octogenarians: the promise of minimally invasive surgery. Spine. 2010;35(26 Suppl):S355–60.
10.1097/BRS.0b013e3182023796 .
doi:
27. Wang MY, Vasudevan R, Mindea SA. Minimally
invasive lateral interbody fusion for the treatment of
rostral adjacent-segment lumbar degenerative stenosis without supplemental pedicle screw fi xation.
J Neurosurg Spine. 2014;21(6):861–6. doi:
014.8.SPINE13841
28. Cho W, Sokolowski MJ, Mehbod AA, Denis F,
Garvey TA, Perl J, Transfeldt EE. MRI measurement
of neuroforaminal dimension at the index and supra-
.
.
.
10.1100/2012/246989 .
.
.
10.1097/
10.1007/
10.3
10.3171/2
1
24 Adjacent Level Disease and Proximal Junctional Kyphosis
241
djacent levels after anterior lumbar interbody fusion:
a prospective study. Clin Orthop Surg. 2013;5(1):49–
10.4055/cios.2013.5.1.49 .
54. doi:
29. Elowitz EH, Yanni DS, Chwajol M, Starke RM,
Perin NI. Evaluation of indirect decompression of
the lumbar spinal canal following minimally invasive lateral transpsoas interbody fusion: radiographic
and outcome analysis. Minim Invasive Neurosurg.
2011;54(5–6):201–6. doi:
30. Ahmadian A, Deukmedjian AR, Abel N, Dakwar
E, Uribe JS. Analysis of lumbar plexopathies and
10.1055/s-0031-1286334 .
nerve injury after lateral retroperitoneal transpsoas
approach: diagnostic standardization. J Neurosurg
Spine. 2013;18(3):289–97. doi:
SPINE12755
31. Aichmair A, Lykissas MG, Girardi FP, Sama AA,
Lebl DR, Taher F, Cammisa FP, Hughes AP. An
institutional six-year trend analysis of the neurological outcome after lateral lumbar interbody
fusion: a 6-year trend analysis of a single institution. Spine. 2013;38(23):E1483–90. doi:
BRS.0b013e3182a3d1b4
.
.
10.3171/2012.11.
10.1097/
Part V
Technical Nuances
Lateral Lumbar Interbody Fusion: A Review of the Current Clinical Outcomes of Different Supplemental Fixation Techniques
Fred Xavier , Brendon Walker , Tucker Callanan ,
Samuel Grinberg , Byung Jo Victor Yoon ,
Celeste Abjornson , and Frank P. Cammisa Jr.
2 5
25.1 Introduction
An average of 2 % of US workers are compensated
for spinal disorders every year [ 1 ]. Back pain rep-
resents the second most common cause of visits to
a physician but the most common one for reduced
workforce among individuals younger than 45
years old [ 2 – 4 ]. Among the group of people who
sought medical treatment, 78 % consulted their
regular physicians, whereas 12 % rushed to the
emergency room of a local healthcare facility. The
fi nancial burden of several hospital visits on the
families and the overall society is enormous. In
2004, the direct annual medical costs were
assumed to reach close to $ 200 billion [ 5 ].
The pathophysiology of low-back pain (LBP)
is multifactorial. Disk degeneration is a leading
cause of spinal instability and LBP. Senescence
of the avascular nucleus pulposus with decreased
transport of nutrients is thought to lead to degenerative disk diseases (DDD), intervertebral disk
space narrowing, and osteophyte development.
The intervertebral disk (IVD) loses its blood supply in the fi rst decade of life [
aging and osteoporosis are also responsible for a
substantial amount of axial bone mass loss result-
F. Xavier , MD, PhD • B. Walker , BS • T. Callanan , BS
S. Grinberg , BS • B. J. V. Yoon , MS • C. Abjornson , PhD
F. P. Cammisa , MD (*)
Spine Care Institute , Hospital for Special Surgery ,
535 E 70th Street , New York , NY 10021 , USA
cammisaf@hss.edu
e-mail:
6 , 7 ]. Moreover,
ing in osteoporosis-related fractures and spinal
deformity [ 8 – 10 ]. The resulting pain and discom-
fort lead to disability and decreased quality of
life. When conservative treatments fail to alleviate the recurrent symptoms, surgical procedures
are advised.
Lumbar spinal interbody fusion surgeries have
been performed for decades to treat patients with
intractable LBP syndromes due to spinal instability, spondylosis, or spinal deformities [ 11 ].
Initially, bone autografts were harvested from the
patient’s body to fi ll the intervertebral disk space
and restore the anatomical curvature while providing mechanical stability until bony fusion.
Complications inherent to the bone graft biomechanics and the donor site morbidities have led to
advanced research in biomaterials and the genesis of various alternatives such as allografts,
metal cages, and poly-ether-ether-ketone (PEEK)
cages [
12 – 14 ]. More importantly, to achieve the
optimal access to the anterior spinal column, several fi xation techniques were developed over the
years based on surgical approaches. This concept, with the primary goal of minimizing local
tissue injuries, is critical to the postsurgical
recovery, spinal stability, and overall functional
success of the procedure.
Introduced by Cloward in 1953 [ 15 , 16 ], the
posterior lumbar interbody fusion (PLIF) offers
great access for posterior instrumentation and the
placement of interbody devices with good fusion
rates [ 17 – 19 ]. However, PLIF is associated with
© 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_25
245
246
F. Xavier et al.
extensive posterior musculature damages [ 20 ,
21 ] and iatrogenic neural injuries [ 22 – 24 ].
Anterior approaches (anterior lumbar interbody
fusion – ALIF), described earlier (in 1948) by
Lane and Moore [ 25 ], allow wider access to the
anterior spinal column. They are also associated
with more life-threatening complications,
namely, injuries to major blood vessels [ 26 , 27 ]
and other internal organ damages [ 28 , 29 ]. The
lateral transpsoas approach (lateral lumbar interbody fusion – LLIF) reduces the neurovascular
complications seen in the anterior and posterior
ones. However, neuromonitoring practices are
required for LLIF since this minimally invasive
technique may add considerable compression to
the surrounding lumbar plexus [ 30 , 31 ].
Despite the numerous achievements of minimally invasive surgical approaches, optimal spinal stability relies on the ability of the implants to
promote fusion between two or more adjacent
vertebrae. Therefore, as done in both anterior and
posterior approaches, laterally inserted cages are
often reinforced with supplemental fi xation.
These additional devices include pedicle screws,
integrated screws, anterior plates, and interspinous process implants. Several authors reported
that supplemental fi xation techniques provide
additional segmental rigidity to aid the fusion
process and prevent cage migration [ 32 ]. This
current review intends to explore the literature
available on the most common devices and procedures used to enhance the biomechanical stability of the LLIF surgeries.
25.2 Pedicle Screw Supplemental
Fixation
By preserving the surrounding soft tissues, standalone lumbar interbody implants placed via lateral approaches reduce the range of motion more
than those from anterior and posterior techniques
[ 33 ]. Still, Watkins et al. [ 34 ] found that the non-
union rate was higher with uninstrumented LLIF
in comparison to other modern fusion techniques.
Cappuccino et al. [ 11 ] found that LLIF with sup-
plemental fi xation decreased the range of motion
more than stand-alone LLIF did. Supplemental
fi xation provides increased stability that is needed
to ensure suffi cient rigidity for the fusion process
to occur [ 35 ].
Currently, the “gold standard” for supplemental fi xation with LLIF is a bilateral pedicle screw
construct [ 36 ]. After the LLIF, the patient is
either repositioned for the posterior fi xation or
the procedure is performed a few days after.
Using bilateral pedicle screws requires a more
invasive operation than a stand-alone LLIF or an
LLIF with other forms of supplemental fi xation.
However, numerous biomechanical studies have
shown that bilateral pedicle instrumentation provides the greatest reduction in range of motion in
all directions [ 11 , 35 , 36 ]. Dougleris et al. [ 36 ]
compared bilateral pedicle screw stabilization to
an interspinous fusion device and found that the
two are similar except that the bilateral screws
provide greater coronal rigidity. In their biomechanical testing of cadaveric spines, Cappuccino
et al. [ 11 ] saw greater range of motion reduction
after LLIF with bilateral pedicle screws than with
either stand-alone implants or lateral plates.
Clinical studies have confi rmed the effi cacy of
bilateral screws but have shown that unilateral
screw fi xation can also be an effective alternative
to bilateral screws. Sharma et al. [ 37 ] examined
the outcomes of LLIF after 1 year. Unilateral
screw fi xation and bilateral screw fi xation were
both included in their study. They found signifi cant improvements in the patients’ VAS (visual
analog score), ODI (Oswestry Disability Index),
and SF-12 (short form-12) physical component
scores. Moreover, the LLIF procedure with pedicle screw fi xation was successful in restoring
lumbar lordosis and correcting scoliosis in
affected patients. Similarly, Kotwal et al. [
reviewed the clinical and radiographic outcomes
of LLIF after at least 2 years. One-, two-, three-,
and four-level procedures were performed
between T12 and L5. Of the 118 patients, 102
received posterior instrumentation. Except for
the lordotic angle at T12–L1, there was signifi cant restoration and correction of disk height,
coronal angulation, and the lordotic angle at all
surgical levels. In patients with degenerative
38 ]
25 Supplemental Posterior Fixation Techniques
247
scoliosis, Cobb angles were also improved. VAS,
ODI, and SF-12 physical component scores all
showed signifi cant improvement. Pawar et al.
[ 39 ] compared patients receiving LLIF with
either unilateral or bilateral fi xation to patients
receiving PLIF and found that LLIF with posterior screw fi xation resulted in lower estimated
blood loss (EBL), fewer surgical complications,
and better radiographic outcomes than PLIF [ 39 ].
Several studies have also specifi cally compared unilateral to bilateral screw instrumentation. Using the transforaminal lumbar interbody
fusion (TLIF) procedure, Chen et al. [ 40 ] com-
pared bilateral and unilateral pedicle screw fi xation in one-level fusions and found that there was
no signifi cant difference between the clinical
outcomes of the two groups after 2 years.
Furthermore, the unilateral fi xation was associated with shorter surgical time, less EBL, and a
faster recovery. Molinari et al. [ 41 ] performed a
review of numerous studies that compared unilateral and bilateral pedicle screw fi xation and
found that the fusion rates when using unilateral
and bilateral pedicle screw fi xation are high and
not signifi cantly different. Since the clinical
results between the unilateral and bilateral procedures are similar, the less invasive unilateral procedure as a supplement to LLIF may be a more
effective option in certain cases.
25.2.1 Case Example
The patient was a 60-year-old male with severe
low-back and right leg pain and weakness in the
right leg and foot. He previously had a laminectomy at the L4–L5 level that provided about two
and a half years of relief. Physical therapy exacerbated his symptoms, and epidural steroid injections failed to provide relief. Figures 25.1 and
25.2 display his preoperative images, which show
lumbar (L4–L5) spinal and right foraminal stenoses, degenerative spondylolisthesis, lumbar
radiculopathy, and a bilateral synovial cyst at
L4–L5. A one-level LLIF procedure was performed. Immediately following the LLIF, the
patient underwent a spinal decompression, excision of the synovial cyst, and posterior bilateral
fusion with bilateral pedicle screws. One year
after surgery, the patient reported a signifi cant
Fig. 25.1 Preoperative
radiographs. ( a ) AP, ( b )
lateral, ( c ) extension, and
( d ) fl exion
248
Fig. 25.1 (continued)
F. Xavier et al.
Fig. 25.2 Preoperative sagittal MRI
improvement in all of his preoperative symptoms. Postoperative radiographs (Fig. 25.3 )
showed solid fusion at L4–L5 with reduced
motion in both fl exion and extension.
25.3 Interspinous Fusion
Interspinous fusion devices are being evaluated
as an alternative to bilateral and unilateral pedicle
screw constructs in augmenting lumbar interbody
fusion rates. The devices are designed to take
advantage of the biomechanical loading processes of the posterior aspect of the vertebral column in order to immobilize the affected segment,
thus stabilizing the spine. The interspinous
devices are intended to create construct stability
comparable to pedicle screws, while being less
invasive, therefore reducing blood loss, risk of
infection, and postoperative muscle pain [
In contrast to interspinous process devices
(IPDs), which primarily work as stand-alone
decompressive materials (i.e., X-STOP), interspinous fusion devices (IFDs) are designed for
fi xation and fusion. Early attempts at interspinous fusion failed, as the pilot implants had a
small surface area with the spinous processes,
meaning all of the force due to the axial load of
the superior spine was applied on a small area.
Contemporary devices include paired plates with
teeth or U-shaped device with wings that attach
to the spinous process [ 46 ].
42 – 45 ].
25 Supplemental Posterior Fixation Techniques
Fig. 25.3 Postoperative
radiographs. ( a ) AP, ( b )
lateral, ( c ) extension, and ( d )
fl exion
249
The US Food and Drug Administration (FDA)
have approved a signifi cant number of IFDs
(Table 25.1 ). Despite the fact that they are com-
posed of different designs and materials, they
share similar indications and implantation techniques with the aim of maintaining a constant
degree of distraction between the spinous
processes and stabilize the spine in a minimally
invasive manner [ 46 ]. As per 510 (k) premarket
notifi cations, the indications for the use of these
devices are to achieve supplemental fusion in the
following conditions: degenerative disk disease
(defi ned as back pain of discogenic origin with
degeneration of the disk confi rmed by history and