SPINE Volum< 26, Number 14, pp 1631-163S
`©2001, Lippincott Williams & Wilkins, Inc.
`
`•
`
`Initial Outcome and Efficacy of "Kyphoplasty" in the
`Treatment of Painful Osteoporotic Vertebral
`Compression Fractures
`
`I.H. Lieberman, MD, S. Dudeney, MD, M.-K. Reinhardt, RN, and G. Bell, MD
`
`Institutional Review Board-ap(cid:173)
`Study Design. An
`proved Phase I efficacy study of inflatable bone tamp
`usage in the treatment of symptomatic osteoporotic com(cid:173)
`pression fractures.
`Objectives. To evaluate the safety and efficacy of in(cid:173)
`flatable bone tamp reduction end cement augmentation,
`ukyphoplasty," in the treatment of painful osteoporotic
`vertebral compression fractures.
`Summary of Background Date. Osteoporotic compres(cid:173)
`sion fractures can result in progressive kyphosis and
`chronic pain. Traditional treatment for these patients in(cid:173)
`cludes bed rest, analgesics, and bracing. Augmentation of
`vertebral compression fractures with polymethylmethac(cid:173)
`rylate, "vertebroplasty," has been used to treat pain. This
`technique, however, makes no attempt to restore the
`height of the collapsed vertebral body. Kyphoplasty is a
`new technique that involves the introduction of inflatable
`bone tamps into the vertebral body. Once inflated, the
`bone tamps restore the vertebral body back toward its
`original height while creating a cavity that can be filled
`with bone cement.
`Patients and Methods. Seventy consecutive kypho(cid:173)
`plasty procedures were performed in 30 patients. The
`indications included painful primary or secondary osteo(cid:173)
`porotic vertebral compression fractures. Mean duration
`of symptoms was 5.9 months. Symptomatic levels were
`identified by correlating the clinical data with MRI find(cid:173)
`ings. Perioperative variables and bone tamp complica(cid:173)
`tions or issues were recorded and analyled. Preoperative
`and postoperative radiographs were compared to calcu(cid:173)
`late the perce-ntage height restored. Outcome data were
`obtained by comparing preoperative and latest postoper(cid:173)
`ative SF-36 data.
`Results. At the completion of the Phase I study there
`were no major complications related directly to use of this
`technique or use of the inflatable bone tamp. In 70% of
`the vertebral bodies kyphoplasty restored 47% of the lost
`height. Cement leakage occurred at six levels (8.6%).
`SF-36 scores for Bodily Pain 11.6-58.7, (P = 0.0001) and
`Physical Function 11.7-47.4, (P = 0.002) were among
`those that showed significant improvement.
`Conclusions. The inflatable bone tamp was efficacious
`in the treatment of osteoporotic vertebral compression
`fractures. Kyphoplasty is associated with early clinical
`improvement of pain and function as well as restoration
`of vertebral body height in the treatment of painful osteo(cid:173)
`porotic compression fractures. [Key words: kyphoplasty,
`vertebral compression fracture, osteoporosis, PMMA
`bone cement, vertebroplasty] Spine 2001;26:1631-1638
`
`From the Department of Orthopaedics, Cleveland Clinic Foundation,
`Cleveland, Ohio.
`Acknowledgment date: June 7, 2000.
`Acceptance date: November 6, 2000.
`Device status category: 3.
`Conflict of interest category: 12.
`
`Osteoporosis is a systemic disease affecting more than 24
`million Americans. It results in progressive bone mineral
`loss and concurrent changes in bony architecture, which
`leave the spinal column vulnerable to compression frac(cid:173)
`tures, often after minimal or no trauma. 17 There arc an
`estimated 700,000 osteoporotic vertebral compression
`fractures (VCFs) in the United States each year, of which
`more than one third become chronically painfuJ.S Ap(cid:173)
`proximately 85% of these fractures are due to primary
`osteoporosis5 and the remainder due to secondary osteo(cid:173)
`porosis or malignancies. These VCFs lead to progressive
`sagittal spine deformity and changes in spinal biome(cid:173)
`chanics and are believed to contribute to a fivefold in(cid:173)
`creased risk of further fracture by virtue of force trans(cid:173)
`mission to weak vertebrae above or below. 10 Whether
`the fracture is painful or not, the spinal deformity caused
`by two or more fractures dramatically impacts health,
`daily living, and medical costs through loss of lung ca(cid:173)
`pacity, loss of appetite, reduced mobility, chronic pain,
`18 The adverse effect on
`14
`and/or clinical depression. 3
`•
`•
`activities of daily living is almost as great as that seen
`with hip fractures. 9 The cost of managing osteoporotic
`VCF patients in the United States in 1995 was $746
`million.16 Osteoporotic VCFs have been shown to be
`associated with up to <1 30% ar~c-adjusred increase in
`mortality12 not observed with osteopo rotic distal radius
`fracture. 4 It has been shown thar there is a 9% loss in
`predicted forced vital capacity with each vertebral frac(cid:173)
`ture, 13 suggesting that the restrictive changes in thoracic
`anatomy are particularly harmful to patients with pre(cid:173)
`existing lung disease. These patients frequently complain
`of the true loss of height because of the fractures and the
`apparent loss of height because of the compensatory hip
`and knee flexion posturing secondary to the progressive
`thoracic and lumbar kyphosis. In summary, osteoporotic
`VCFs pose a significant clinical problem including pain,
`spinal deformity, reduced pulmonary function and mo(cid:173)
`bility, and an overall increase in mortality in this vulner-
`able group of patients.
`'
`Traditional treatment for patients with osteoporotic
`VCFs includes bed rest, analgesics, and bracing. This
`type of medical management obviously does nothing to
`restore spinal alignment, and the lack of mobility itself
`can increase the rate of demineralization. 10 Because of
`the inherent risks and invasive nature, surgical treatment
`of osteoporotic VCFs has been limited to cases in which
`there is concurrent spinal instability or neurologic com(cid:173)
`promise. Reconstruction with structural bone graft and
`instrumentation may be performed from an anterior or
`
`1631
`
`•
`
`STRYKER EXHIBIT 1030, pg. 1
`
`STRYKER CORPORATION v. ORTHOPHOENIX, LLC
`
`IPR2014-01519
`
`

`
`Figure 1. Inflatable bone
`tamp.
`
`posterior approach; however, the success of these tech(cid:173)
`niques is limited by the patient's poor bone quality and
`general medical condition.
`Augmentation of VCFs with polymethylmethacrylate
`(PMMA), "vertebroplasty" was first de.scribed by Gali(cid:173)
`bert ct al in 1987 for use in vertebral body tumors. 8 It
`involves the forced injection of low viscosity PMMA ce(cid:173)
`ment into the closed space of the collapsed vertebral
`body. Intra vertebral pressure is therefore required to en(cid:173)
`able low viscosity cement to infiltrate the compressed
`vertebral body. Although vertebroplasty is currently be(cid:173)
`ing used successfully for pain relief in VCFs,1
`15 this
`6
`7
`•
`•
`•
`technique makes no attempt to restore the height of the
`collapsed vertebral body. The principal limitation of ver(cid:173)
`tebroplasty is cement extravasation, the rates of which
`are as high as 65% in metastases19 and 30% when used
`to treat osteoporotic fractures. 11
`"Kyphoplasty" is a new technique with a number of
`potential advantages. This technique was conceived and
`developed by Dr. Mark Reiley (Berkley, CA). It involves
`the introduction of a cannula into the vertebral body,
`followed by insertion of an inflatable bone tamp (IBT)
`designed to reduce the vertebral body back toward its
`original height, while creating a cavity to be filled with
`bone cement. The cement augmentation is therefore
`done with more control into the low-pressure environ(cid:173)
`ment of the preformed cavity with viscous partially cured
`cement in an attempt to reduce the risk of extravasation.
`In this Phase I study we a imed to eva luate the efficacy
`of using IBT reduccion and ccmem augmentation, ky(cid:173)
`phoplasty, in the treatment of painful osteoporotic ver(cid:173)
`tebral compression fractures. Our emphasis is on ease of
`application, positioning, and safety, of the IBT, and ex(cid:173)
`tent of fracture reduction. We also aimed to examine the
`rate of cement extravasation and early patient outcomes.
`
`• Methods
`This study was designed as a single cohort study using consec(cid:173)
`utive prospectively gathered data examining early outcome and
`radiographic vertebral height restoration in no less than 20
`patients after kyphoplasty for osteoporotic compression frac-
`
`tures. The end point of this Institutional Review Board(cid:173)
`approved study was 3 months.
`
`Patients Seventy consecutive kyphoplasty procedures were
`performed in 30 patients over 38 sessions from April1999 ro
`March 2000. The mean age was 68.6 years (range 48-86
`years). The indications included painful primary (n = 19) or
`secondary (n = 5) osteoporotic vertebral compression fractures
`for a total of 24 patients unresponsive to nonoperative meth(cid:173)
`ods. A further six patients presented with painful compression
`fractures from multiple myeloma. The mean duration of symp(cid:173)
`toms was 5.9 months (0.5-24 months). Symptomatic levels
`were identified by correlating the clinical data with MRI find(cid:173)
`ings of marrow signal changes consistent with compression
`fractures. MRI was also used to confirm the presence of a true
`wedge compression fracture and rule out burst-type injuries
`with retropulsed bone.
`
`Kypboplasty Technique IBT placement involves identifying
`an extrapedicular or transpedicular entry point into the verte(cid:173)
`bral body using a guide pin, with the use of biplanar fluoros(cid:173)
`copy (Figures 1 and 2). This is followed by placement of a
`cannulated obturator over the guide wire. The obturator is then
`tapped into the bone over the guide wire. A working cannula is
`placed over the obturator and advanced until the tip of the
`cannula is seated in the posterior portion of the vertebral body.
`A hand-mounted drill bit is then used to ream a corridor for the
`IBT to be passed through. The IBTs are ideally situated under
`the collapsed endplate on the lateral radiograph. Inflation is
`slowly performed under fluoroscopy as are all stages of guide
`wire, obturator, and cannula placement. The inflation pressure
`of the lRT is monitored closely during inflation via an in-line
`pressure gauge. Inflation is continued up to a maximum pres(cid:173)
`sure of 220 psi or the maximum size dependent balloon volume
`is reached. Inflation should also be stopped if the balloon abuts
`any one of the cortical margins. When a suitable cavity has
`been prepared and as much reduction is achieved as is possible,
`the PMMA cement augmented with barium is mixed. Smaller
`cement cannulas, which fit inside the working cannula, arc
`filled with cement. Before its application the cement is allowed
`to thicken. A 2-cm 3 bolus of cement is repeatedly suspended
`from a wooden spatula, and when the viscosity is such that the
`cement does not fall from the spatula, it is ready for injection.
`The cement cannula is advanced through the working cannula
`
`STRYKER EXHIBIT 1030, pg. 2
`
`

`
`Kyphoplasty and Vertebral Compression Fractures • Lieberman et al 1633
`
`cannulation
`
`channel creation
`
`balloon tamp inflation
`
`resultant cavity
`
`cement application
`
`final cement fill
`
`Figure 2. Kyphoplasty steps, lateral fluoroscopic Images.
`
`to the anterior vertebral body wall, and cement is slowly ex(cid:173)
`truded using a stainless steel stylet, which acts as a plunger.
`Filling is performed under continuous lateral fluoroscopic
`guidance. The use of the stylet and bone filler cannula enables
`cement to be applied at considerably higher viscosity than pos(cid:173)
`sible with injection through a 5-mL syringe and 11-gauge nee(cid:173)
`dle. Cement filling is stopped when the cement mantle reaches
`two thirds of the way back to the posterior vertebral body
`cortex on the lateral fluoroscopic images. The number of ce(cid:173)
`ment cannulas that need to be prepared is estimated from the
`final inflation volume achieved with the IBTs. Often the volume
`applied is 1-2 mL greater than the final inflation volume allow(cid:173)
`ing cement from the central bolus to interdigitate with the sur(cid:173)
`rounding cancellous bone.
`
`Measurement of Height Restored: Radiographic Assess(cid:173)
`ment The vertical height of all fractured vertebrae were mea(cid:173)
`sured both before and after surgery (Figure 3). Vertebral height
`was defined as the distance (endplate to end plate) at the center
`of the vertebral body on the lateral radiograph. The vertical
`height of the vertebra above the fractured vertebra was also
`measured to give an estimate of the prefracture height. Calcu(cid:173)
`lations were made as follows: height regained = (post"
`treatment height - pretreatment fractured height), height lost
`= (estimated prcfracture height - prctreatmenr fractured
`height), percentage of height lost that is now restored = (height
`regained/height lost) X 100. The abso.lute values in height
`(mm) pretreatment and posNreatment were statistically com(cid:173)
`pared using paired nonparametric analysis (Wilcoxon signed
`rank rest). Repeat measurements of the same vertebral levels
`after a 2-week interval with the same observer demonstrated an
`error of::': 1.1 mm.
`
`Assessment of Cement Leakage Cement leakage was re(cid:173)
`corded prospectively at surgery. Postoperative radiograpbs
`
`were also examined for the presence of leakage of cement.
`Cement leakage was recorded on the basis of position and
`correlated with any postoperative clinical symptoms.
`
`Measurement of Early Outcome; Clinical Assessment
`Outcome data were obtained by comparing preoperative and
`latest postoperative SF-36 data. Patients completed the SF36
`questionnaire without assistance if feasible at the time. of their
`preoperative assessment and at subsequent 1-, 6-, and 12"week
`follow-up appointments. The Wilcoxon signed rank test was
`used for statistical analysis of SF-36 data. A P value o( < 0.05
`was deemed significant.
`
`• Results
`All 30 patients tolerated the procedure well, and im(cid:173)
`provement in pain and mobility was seen early. Virtually
`all patients subjectively reported immediate relief of their
`typical fracture pain, and no patient complained of
`worse pain at the treated levels. The levels treated ranged
`from T6 to L5, the majority at the thoracolumbar junc(cid:173)
`tion (Tll = 8, Tl2 = 15, L1 = 12). The ratio of general
`to local anesthesia used was 6:1. Kyphoplasty was per(cid:173)
`formed via transpedicular and cxtrapedicular routes in
`40% and 60% of cases, respectively. After surgery all
`patients were admitted to the 23-bour stay unit. Twenty
`patients were discharged home the following morning,
`seven were discharged that same afternoon, five re(cid:173)
`mained 2 days, four remained 3 days, one remained 16
`days, and one patient remained as a long stay inpatient
`because of premorbid conditions.
`In all cases a cavity was successfully created in the
`vertebral body. The average cavity/IBT volume was 2.6
`mL (range 0.5-5.0 mL). The average lBT inflation pres-
`
`STRYKER EXHIBIT 1030, pg. 3
`
`

`
`1634 Spine o Volume 26 o Number 14 o 2001
`
`Post height = 3 7mm
`Mid height= 20mm
`Kyphosis = 16 deg
`
`Post height = 3 7mm
`Mid height= 12mm
`Kyphosis = 25 deg
`
`Post height = 3 7mm
`Mid height= 28mm
`Kyphosis = 10 deg
`
`operative lateral radiographs, measurement of vertebral
`height was difficult in that the endplates could not rea(cid:173)
`sonably be defined. In these cases an estimate was used,
`or if this were not possible, no value was obtained for
`that level. At four levels we had complete restoration,
`and in 15 there was no appreciable height restoration.
`SF-36 scores for Bodily Pain, Physical Function, Role
`Physical, Vitality, and Mental Health all showed im(cid:173)
`provement (Table 1 and Figure 5). Bodily Pain scores
`
`Figure 3. Example of height restoration and measurement.
`
`sure was 130 psi (range 70-250 psi). In 14 cases the IBT
`ruptured during the procedure. All but one of the rup(cid:173)
`tures was a pinhole in the balloon component, reflecting
`puncture by sharp pieces of bone. Most of the failures
`occurred after maximum inflation was achieved and a
`replacement IBT was not required. In three cases the IBT
`failed earlier in the procedure and a replacement was
`required. In all instances the ruptured tamp was easily
`withdrawn. Balloon inflation asymmetry was noted dur(cid:173)
`ing the early stages of inflation in some cases. In most
`instances further inflation resulted in a more symmetric
`pa ttem. It was thought that this was a consequence ofthe
`IBT meeting bone of different densities.
`Radiologic height measurement of all 70 levels treated
`demonstrated that the mean central vertebral height lost
`was 8.7 mm (range 2-17 mm). The mean percentage of
`height lost that was restored by the procedure was 35%
`(range 0-100%). Examination of the data graphically,
`however, showed a non-Gaussian distribution with rwo
`subsets of patients (Figure 4 ). The vertebral levels treated
`can be divided into those in which some height was re(cid:173)
`stored (70%) and those in which no height was restored
`(30%). When the group in which height was restored is
`examined separately the mean height restored is 46.8%.
`The distribution of this group is uniform (not bimodal);
`therefore, the term mean here has greater validity. The
`absolute mean height gain for the latter group is 4.1 mm
`(P = 0.001) compared with 2.9 mm (P = 0.001) when all
`levels treated are considered.
`In some instances because of the osteopenic nature of
`the bone or the quality of either the preoperative or post-
`
`Levels
`.
`16
`
`14
`
`12
`
`10
`
`8
`
`6
`
`4
`
`2
`
`0
`
`0 ·
`l 0%
`
`11-
`200/9
`
`1', n
`
`61·
`Sl·
`41·
`31·
`21·
`700/o
`60%
`50%
`40%
`30%
`Percentage height restored
`
`71·
`RO%
`
`81·
`90%
`
`91·
`1 OO'h
`
`Figure 4. Percentage height restoration, single midline measure,
`average duration of symptoms = 5.9 months.
`
`STRYKER EXHIBIT 1030, pg. 4
`
`

`
`Kyphopl3sly and Vertebral Compression Fractures • Lieberman et at 1635
`
`Table I. Patient Information, Height Measurements, and SF-36 Data
`
`Duration of
`Prefracrur• %Height
`St;'ptomst Follow-Up Levels
`Post Rx
`Pre Rx
`onths Months Treated HeighVmm HeighVmm HelghtJmm Restored
`
`Patlant
`
`SF-36 Pratreatment
`
`SF-36 Post-treatment
`
`rost-Ojllll'etlve
`Hosga~l StavfOnf
`(0.> = Oaytasa
`
`2
`
`3
`
`G
`
`1
`B
`
`g
`
`10
`11
`12
`
`13
`
`0,8
`2.2
`
`2
`
`12
`
`11.5
`
`6.7
`
`15
`
`7
`
`13.6
`
`2
`24
`
`2
`
`4
`1
`18
`
`10.5
`10
`
`12.4
`
`2.5
`2
`8.7
`
`10
`
`10
`
`16
`17
`20
`15
`17
`15
`Z2
`24
`15
`11
`17
`15
`17
`
`9
`15
`16
`11
`15
`12
`17
`
`20
`23
`
`17
`17
`21
`13
`20
`
`19
`21
`20
`11
`17
`23
`28
`28
`15
`11
`20
`20
`21
`
`17
`20
`16
`16
`17
`18
`17
`
`20
`27
`
`17
`17
`22
`15
`20
`
`15
`15
`16
`
`24
`24
`22
`25
`2S
`25
`2S
`2S
`18
`18
`25
`25
`25
`
`Z2
`22
`22
`20
`20
`20
`20
`
`30
`30
`
`22
`25
`25
`25
`30
`
`zg
`33
`30
`
`0'11*0*75"20*1 2.s•-"92
`
`70"0*1 OO*n*50"8B*-"92
`
`0'11*12*35'35*12.5*100*1111 70'11*74*47*66*75*50"110
`
`38% 35*25*32"67*15*75*100"72 25"0*74*57~4D*SS•&7"76
`57%
`0
`20%
`0
`80
`100
`100
`0
`D
`37.5
`50
`50
`
`20*8*1 0*82*30"0*1 00*72
`
`85*75*41 *82*65*88*1 00'92
`
`0"0"0"-*35'60*100*72
`
`50*0*4 1 *77*50•62.5*1 00*1111
`
`0.5
`1
`1
`1
`
`B
`
`1
`3
`
`0.5
`
`62
`71
`0
`56
`40
`76
`0
`
`0
`57
`
`0
`0
`25
`17
`D
`
`26
`0
`18
`
`0'11*0*67"11*0*0•36
`
`1 5*0*22*40*40"37 .5*0*40
`
`5* 0"0"92*5"25*1 00*56
`0*0'0*55*80*0*1 00*84
`
`95*1 00*84*n"35*50'1J•ez
`0*0*42*57"90*12.5'100*76
`
`5"0*22*20"35*25*100*60
`
`0"11*22*55*5*50'11*56
`
`5'1J*22"3fi*35*50'1J*B0
`
`80"25*74*27*65*100*100*96
`
`3
`long stay
`1
`
`25*0*42*42*20*100*0*52
`
`50"11*84*65*25*62.5"100*92
`
`0-5
`
`80"0*22*50'80"75*100*80 80*100*100'62*50'100'100*60
`
`TS
`L1
`L2
`TB
`no
`112
`T9
`112
`L1
`T11
`T12
`T11
`112
`L1
`L2
`L3
`T11
`112
`L1
`n
`T10
`T11
`T12
`L4
`L6
`L1
`l1
`n
`T9
`T11
`T12
`L1
`L4
`L5
`T12
`L6
`112
`T12
`1.3
`L5
`T12
`L1
`112
`L3
`L3
`T6
`T9
`Tll
`L1
`LS
`TS
`T8
`TS
`T11
`T12
`L2
`T12
`L1
`L2
`T9
`T12
`T11
`L1
`L2
`n
`T6
`T8
`L3
`L1
`L3
`
`10
`15
`13
`
`17
`
`16
`6
`16
`
`10
`20
`
`20
`15
`22
`
`25
`28
`285
`
`21
`25
`28
`7
`
`19
`15
`23
`
`14
`15
`
`16
`
`17
`18
`19
`20
`
`21
`
`22
`23
`
`24
`
`25
`
`26
`
`27
`28
`
`28
`30
`
`0.5
`0.5
`
`24
`24
`4
`6
`
`0.8
`3
`
`1.5
`
`3
`
`8
`1
`
`1
`6
`
`1.3
`
`2.0
`7.1
`
`9
`
`8.3
`5.3
`
`7.0
`
`0.8
`
`0.8
`6.4
`
`6.0
`6.0
`
`19
`
`18
`9
`21
`
`22
`20
`
`20
`20.4
`21.6
`
`26.4
`3D
`3D
`
`23.4
`311.8
`30.B
`7
`
`21i
`20
`25.3
`
`25
`
`22
`22
`23
`
`28
`30
`
`Z6
`27
`27
`
`3D
`30
`30
`
`28
`33
`33
`20
`
`36
`27
`33
`
`25
`
`33
`19
`71
`
`67
`0
`
`0
`45
`0
`
`2S
`100
`100
`
`34
`73
`56
`0
`
`35
`42
`23
`
`15'11*12°40*0*0*0*44
`
`60*0*52'62'25'50*0*76
`
`0"0"0*72*0'12.5*67*40
`
`90*100*74"87*80*100*100*68
`
`50*100*100*65*50*100*100*84
`5*0*22"45*20*38*0*28
`20*11"12*20*35*25*1 00"110 70*25*52'1 0*50*75"1 00'66
`
`5"0"0*40*35*83*100"64
`
`55*0'41"117"35*62.5'11*52
`
`5*0*12*50"20*13"0*60
`
`5'11*31"115"00*87 .5*100*92
`
`15"11*12*82'30*25*1 00*52 15*0*0*82*45"25"0*80
`0*0"0*97"0"0*100*80
`15*0*62*67*60*50*100*96
`
`5"0"12*20*10*0*100*40
`
`45*100"62*60"35*87.5.100'84
`
`2
`3
`
`16
`
`2
`o.s
`0,5
`u.s
`
`2.0
`
`0.6
`1
`2
`1
`1
`
`• SF-36 Scores ere separated by an asterisk. The aight scores ere physical function, role function, bodily pain, gene<al health, vitality, social functioning, role
`emotional, mental health.
`
`STRYKER EXHIBIT 1030, pg. 5
`
`

`
`1636 Spine • Volume 26 • Number 14 • 2001
`
`80
`70
`
`50
`
`40
`
`30
`
`~~~ /
`
`~
`
`Cpre
`•post
`
`+ Age mulch norm
`
`60 ~ -.:
`!0 ~ _0 J ,!J
`10 D
`
`0
`
`PF Rl' BP GH v
`Figure 5. SF-36 outcome scores, pre- and post-treatment.
`
`SF RE MH
`
`improved from 11.6 to 58.7 (P = 0.0001). Physical
`Function improved from 11.7 to47.4 (P = 0.0020). Role
`Physical improved from 1.2 to 29.8 (P = 0.57). Vitality
`scores improved from 24.8 to 47.9 (P = 0.0013). Mental
`Health improved from 59.2 to 71.1 (P = 0.015). Social
`Functioning improved from 28.6 co 69.0 (P = 0.0004).
`General Health and Role Emotional scores did not show
`significant improvement.
`Cement extravasation was seen at six levels (8.6%).
`Cement entered the epidt1ra l space in one patient, the
`disc space on two occasions, :md t.he paraspinal tissues in
`three cases. As soon as tbis was seen on the fluoroscope,
`cement injection was stopped. No problems were identi(cid:173)
`fied clinicallv as a result of these extravasations immedi(cid:173)
`ately after st;rgery or at final follow-up. In the one case of
`cement in the epidural space (T12Ievel), the cement lay(cid:173)
`ered around the base of the pedicle. At the time it was
`thought that cement was injected prematurely allowing it
`to flow out a small venous sinus. In the remaining cases
`cement appeared to leak through the superior endplate
`or a sidewall crack.
`At final follow-up (mean= 6. 7 months) there were no
`major complications related directly to the use of this
`technique or the IBT. There were no injuries to spinal or
`extraspinal tissues as a result of guide pin, obturator, or
`cannula placement. Bone tamp expansion was bounded
`by the vertebral body, and a cavity was created success(cid:173)
`fully in all cases. One patient developed perioperative
`pulmonary edema and a myocardial infarction second(cid:173)
`ary to intraoperative fluid overload. Rib fractures oc(cid:173)
`curred in two patients related to positioning.
`
`• Discussion
`
`The results of this initial series of patients show that
`kyphoplasty is a well-tolerated procedure indicated for
`the treatment of painful VCFs. Kyphoplasry is associated
`with early clinical improvement of pain and function as
`well as restoration of vertebral body height.
`We anticipate much debate in the near future in dif(cid:173)
`ferentiating the kyphoplasty from the vertcbroplasty
`technique. On the basis of pain relief, this will be difficult
`as excellent pain relief is seen with both techniques.
`However, our findings support the differentiation of the
`two techniques on the basis of height restoration and risk
`
`of cement extravasation. Our findings of low rates of
`cement extravasation in kyphoplasty, compared with
`published vertebroplasty series, stlpport the hypothesis
`that injection of high-viscosity cement into a previously
`formed cavity is a significant improvcmen~ over the in(cid:173)
`jection of low-viscosity liquid cement into the unreduced
`vertebral body, on the grounds of safety alone. Restora(cid:173)
`tion of height and sagittal aUgrunenrwill work to protect
`vulnerable vertebral levels a bove or be low by minimizing
`force transfer. Kyphoplasry may have an advantage in
`this regard, but its true benefit will only be borne our in a
`longer-term study of subsequent fractures.
`The method we used to detect height restoration ex(cid:173)
`amines central vertical height restoration on lateral plain
`radiographs. Although height restoration was seen, this
`is a crude method of assessment. It does not measure the
`actual deformity as a whole. For our ongoing study we
`now use preoperative and postoperative 3-foot standing
`lateral radiographs to measure the kyphosis and the ver(cid:173)
`tebral body height. We are also devising alternate imag(cid:173)
`ing methods to measure restoration of vertebral body
`volume in addition to height. In this study we made no
`attempt to stratify or account for age of fracmre because
`all comers were included in this efficacy study. We believe
`this has skewed the height restoration results. In the en(cid:173)
`tire group we saw a 35% restoration of vertebral height,
`but longer follow-up is required to see if this will be
`maintained. A number of the levels treated were more
`chronic, and in some we were able to restore height and
`in others we were not. However, despite the chronic na(cid:173)
`ture of some fractures, we were able to produce a cavity
`in all vertebrae treated, and in this initial experience we
`got the impression that we were more predictably able
`to restore height in those fractures less than 3 months
`of age.
`This Phase I efficacy study suggests that kyphoplasty is
`a safe procedure. The IBT functioned well and restored
`vertebral height. Clinical improvement often occurred in
`the first 24 hours after surgery. In some, successful ky(cid:173)
`phoplasty enabled the elderly patient to mobilize, having
`previously been unable to so. It is po&sible tbar in the
`future kyphoplasty may be shown to be worthwhile im(cid:173)
`mediately after vertebral fracture in some high-risk pa(cid:173)
`tients to enable early mobilization and decrease mortal(cid:173)
`ity. In distal radius fractures or hip fracture we are
`reluctant to accept biomechanically compromised align(cid:173)
`ment. In the spine we no longer have to accept a biome(cid:173)
`chanically or physiologically compromised situation be(cid:173)
`cause we now have a method of early reduction and
`stabilization for patients with osteoporotic compression
`fractures. Considering the increased mortality associated
`with osteoporotic compression fractures, early mobiliza(cid:173)
`tion in these patients is of prime importance, synony(cid:173)
`mous with the elderly hip fracture population.
`There is also considerable interest in the use of a bio(cid:173)
`compatible bone cement substitute in the augmentation
`of osteoporotic compression fractures. 2 With the use of
`synthetic bone products we anticipate prophylactic inter-
`
`STRYKER EXHIBIT 1030, pg. 6
`
`

`
`diagnosed \'e:rtrbr3l fractures: a population-based study in Rochester, Min(cid:173)
`ntsota, 19H.5-1989. 1 Uone Miner Res 1992;7:221-7.
`6. Corter B, Cotton A, Boutr~· N, et al. Percutaneous vertehroplasty in the
`t1eatme11t of osteoporotic vertebrc\l compression fr11ctures: an open pros pee·
`tivc study. 1 Rheumatol 1999;2.6:2222-8.
`7. Deramond H, Deprit'ster C, Galibert P) Le Gar~ D. l)crcutaneous verlebro·
`plasty with polymcthylmethac.rylate: technique, indications and result•. Ra·
`diol Clin North Am 1998;36:533-46.
`8. Galibcrt P. Derarnond H. Nor~ prilirninaire sur le traircment des angiomc.s
`"Yerttbraux par vcrr€broplr.srie acr)'liquc percutanCc. Neurochirurgie 1987;
`33:166-7.
`9. Greendale GA, llarrett-Connor E, Ingles S, HaileR. !.•t< physical and func·
`tiona! effects of osteoporotic fra.cturr.s in women: the Rancho Bernardo
`Study . .J Am Geriotr Soc 1995;43:955-61.
`I 0. Heanq• RP, The natural history of vercebral osreoporosi.o;;: is low bone mass
`an epiphenomenon? Bone 1992; 13(suppl 2):2.>-6.
`1 I. Jensen ME, Evans A], Mathis JM, Ka!lrnes DF, Cloft Hj, Dion JE, Percuta(cid:173)
`neous polymethy!mcthacrylate vertebropbsty in the treatment of oste:opo(cid:173)
`rotic vertebral body c.:ompresslon fractures: tc:c:hnical aipcct(O. A•n] Nt"uro(cid:173)
`radioi1997;1S:1897-904.
`12. Kado D?vf, Browner WS. Palermo L, Nevitt !v1C, Ccna.nt HK, Cummings1
`SR. Vcrrebral fractures and mortality in older women: a prospective study.
`Arch Intern Med 1999;159:1215-20.
`1.1. I.eech1A, Dulberg C, Keliie S, Pattie L, Gay j. Relationship of lung function
`to severity of osteoporosis in women. Am Rev Respir Dis 1990;141:68-71.
`14. Lyles KW, Gold DT, Shipp KM, l'iepcr CF, Martine>. S, Mulhauscn, PL.
`Association of osteoporotic \'Cttebra ! fracnaes with impaired functional sta(cid:173)
`tus. 1\m J Med 1993;94:595-601.
`15. M3this jJv1, Petri M, Naff N. Percutaneous verrebroplasty uecwnent of ste(cid:173)
`roid-induced osteoporotic compression fractures .A rthdtis Rheum 1998;41:
`171-.S.
`Jr;. Melton LJ Ill. Epidemiology ui spinal osteoporosis. Spine J997;22jsuppl):
`2-11.
`17. Ri~~' BL, Melton LJ Ill. ln,•oludonal osteoporosis. N Engi.J Med !9H6;314:
`"1676-86.
`18. Silverman SL. Tl)e clinical consequences of vertebr:d compression fraclurr;:.
`Bone l992;13(suppl 2),17-3 i.
`19. Weill A, Chiras J, Sirnon JM, Rose M, Sola·Martin<z T, Enkaoua E. Spinal
`merastascs: indications for and results of percur:me01.1S injection of acrylic
`ccmenr. Radiology 1996;199:241-7.
`
`Address reprint requests to
`
`I.H. Lieberman, MD
`Minimally Invasive Surgery Cente~·
`9500 Euclid Ave., Desk .4.-41
`Cl1•velalld, OH 44195
`E-mail: lieberi@ccf.org
`
`Kyphoplasty and Vertebral Compression Fractures • Liehcmtan ct al 1637
`----
`vention to prevent painful collapse. Until the efficacy of
`these substances is tested in the spine, one of the major
`questions in this procedure as it is now performed is as
`follows: "What is the natural history of cement in the
`osteoporotic vertebral body over 20-30 years?"
`The long-term benefits of kyphoplasty arc currently
`being studied in a multicenter Phase II randomized con(cid:173)
`trolled trial.
`
`Acknowledgment
`
`The authors thank Kyphon Inc. (Sunnyvale, CA) for pro(cid:173)
`viding the equipment and technical support for this
`study.
`
`• Key Points
`
`• Kyphoplasty using the inflatable bone tamp is a
`safe and effective technique to reduce and stabilize
`osteoporotic vertebral compression fractures
`• The inflatable bone tamp was able to restore lost
`vertebral height and create a cavity for cement fill.
`• The cement fill can be performed under low pres(cid:173)
`sure with viscous cement, thus minimizing the risk
`of cement leakage.
`
`• Kyphop\asty was associated with a statistically
`significant improvement in pain and function as
`measured with SF-36 in patients with vertebral
`compression fractures.
`
`References
`
`1. Barr JD, Barr MS, Lemley TJ, McCann RM. l'ercutaneous 1•ertebroplasty for
`pain relief and spinal stabilisation. Spine 2000;25:923-S.
`2. Bo!ltrum MPG, Lane ]l\1 . Puture Jircctions: augment3tion of osteoporotic
`vertebral bodies. Spine 1997;2.2(suppl):38-42.
`J. Cook DJ, Guyatt GH, Adachi JD, et al. Quality of life im1es in women with
`vertebral fractures due ro osteoporosis. Arthriris Rheum 1993;36:7.50-6.
`4. Cooper C, Atkinson Ej,Jacobsen Sj, et al. Population-based study of survival
`after osteoporotic fra•tures. Arn .J Epidemiol199.3;137:100!-5.
`5. Cooper C, Atkinson EJ, O'Fallon WM, Melton LJ HI. Incidence of clinical!y
`
`Point of View
`
`Nancy Birkmeyer. PhD
`Department of Surgery
`Dartmouth Medical School
`Hanover, New Hampshire
`
`The techniques of percutaneous vertebroplasty and ky(cid:173)
`phoplasty for treating osteoporotic compression frac(cid:173)
`tures are rapidly disseminating throughout the United
`States and Europe. These new treatments for osteopo(cid:173)
`rotic vertebral fractures involve augmentation of the af(cid:173)
`fected vertebral bodies with acrylic bone cement. Inky(cid:173)
`phoplasty an inflatable bone tamp is used in an effort to
`
`restore vertebral height and create a cavity for the inser(cid:173)
`tion of cement. Kyphoplasty therefore offers the possible
`advantages over vertebroplasty of reducing spinal defor(cid:173)
`mity and risks of cement leakage.
`Despite increasing use, little is known about the effec(cid:173)
`tiveness of these