Adult Degenerative Scoliosis: Evaluation and Management

Neurosurg Focus 28 (3):E1, 2010

Adult degenerative scoliosis: evaluation and management

Fe r n a n d o E. Si l v a , M.D.,1 a n d La w r e n c e G. Le n k e , M.D.2 1Harris Methodist Fort Worth, Neurological Surgery, North Texas Neurological and Spine Center, Fort Worth, Texas; and 2Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri

Degenerative scoliosis is a prevalent issue among the aging population. Controversy remains over the role of surgical intervention in patients with this disease. The authors discuss a suitable approach to help guide surgical treatment, including decompression, instrumented posterior spinal fusion, anterior spinal fusion, and osteotomy. These treatment options are based on clinical analysis, radiographic analysis of the mechanical stability of the deformity, given pain generators, and necessary sagittal balance. The high potential complication rates appear to be outweighed by the eventual successful clinical outcomes in patients suitable for operative intervention. This approach has had favorable outcomes and could help resolve the controversy. (DOI: 10.3171/2010.1.FOCUS09271)

Ke y Wo r d s • degenerative scoliosis • decompression • fusion

e n e r a l l y , scoliosis can be divided into 2 types: patients older than 40 years and without a history of nonstructural and structural. The nonstructural AIS.27 These are lumbar curves measuring > 10° with type includes postural, hysterical, sciatic, inflam- associated distal fractional curves. Although these lum- Gmatory, and compensatory scoliosis, and some of these bar curves are not associated with structural thoracic can become structural. The key is that the curve has no curves, compensatory thoracic curves can occur. As in rotatory component. On the other hand, structural sco- AIS, curve prevalence in ADS is inversely proportional liosis includes congenital, neuromuscular, idiopathic, de to curve magnitude. The prevalence of 10°, 10–20°, and > novo, traumatic, and iatrogenic types among others. Our 20° curves is 64, 44, and 24%, respectively. These curves focus is on structural scoliosis in the adult population— have roughly a 1:1 female/male ratio and are rarely pres- more specifically, de novo ADS. ent before the age of 40 years, with a mean age of 70.5 Adult scoliosis is a spinal deformity in a skeletally years at the time of presentation.14 mature individual, with a curve measuring > 10° ac- cording to the Cobb method.12 Scoliosis in adults can be further divided into idiopathic and de novo types. Adult Natural History idiopathic scoliosis refers to a patient with a history of Patients with ADS typically present in the 6th decade AIS with increasing symptoms or progression of the de- with symptoms of spinal stenosis. They can also present formity into adulthood. In ADS, the curve develops dur- with a history of back pain that is worsening, radiculopa- ing adulthood due to the degeneration of spinal motion thy, or a combination. Symptoms from spinal stenosis in segments.4,14 Generally, the deformity begins as the inter- this group of patients are not relieved by forward posture, vertebral disc starts to deteriorate, with ensuing degen- as has been noted in those with neurogenic claudication eration and eventual lack of competency of the posterior not associated with scoliosis, unless a patient sits with his elements, especially the facet joints.25 Thereafter, axial or her trunk supported by the arms. This distinction is rotation of the involved spinal segments leads to lateral important because the prognosis and treatment of ADS olisthesis, and ligamentous laxity occurs. are different from those in patients with degenerative spinal stenosis. Similar to AIS curves, which can progress ° Demographics into adulthood, ADS curves tend to progress 1–6 per year (average 3° per year).25 Osteopenia seems to play a Adult scoliosis prevalence ranges from 1 to 10%.17,24,28 role in this progression, but this hypothesis has been re- This new-onset deformity is observed in more than 30% futed.26,27,31 Nonetheless, certain parameters do appear to of elderly patients with no history of spinal abnormali- factor into curve progression.25 Patient age and sex do not ties.4,27 Degenerative scoliosis is typically diagnosed in affect curve progression in this category of defomity.18 Curves with Cobb angles > 30°, an apical rotation greater Abbreviations used in this paper: ADS = adult degenerative sco- than Grade II, a lateral olisthesis > 6 mm, and an inter- liosis; AIS = adolescent idiopathic scoliosis; ASF = anterior spinal crest line through L-5 appear to have a higher degree of fusion; TLIF = transforaminal lumbar interbody fusion. progression.25

Neurosurg Focus / Volume 28 / March 2010 1

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC F. E. Silva and L. G. Lenke

TABLE 1: Lenke-Silva levels of treatment for operative ADS: clinically and radiographically based decision making matrix*

Nonop Symptom Management Level I Level II Level III Level IV Level V Level VI neurogenic claudication/ minimal + + + + + + radiculopathy back pain minimal minimal +/− + + + + ant osteophytes + + − − − − − olisthesis − − − + + + + coronal Cobb (<30º) − − − + + + + lumbar kyphosis − − − − + + + global imbalance − − − − − + (flexible) + (stiff/ fused)

* See text (Six Levels of Operative Treatment: Lenke-Silva Treatment Levels I–VI) for specific descriptions of levels of treatment. Abbreviations: ant = anterior; + = present; − = absent.

Evaluation joints and trochanters are palpated and evaluated for any hip or knee contractures, and the degree of flexibility is A thorough history and general physical examination are completed. More specifically, a history of idio- noted. Finally, cardiopulmonary, bone quality, nutritional, pathic scoliosis is elicited to discount the possibility of and general health statuses are evaluated to determine if a degenerative idiopathic deformity. In addition, patients the patient is a suitable operative candidate. are asked if they have experienced any changes in body habitus, gait, or how their clothes fit. Pain is investigated in terms of its initial onset, location, duration, charac- teristics, aggravating/relieving factors, and any previous modalities of treatment. A crucial question is whether the pain is purely axial or is also radicular in nature. Axial pain is more likely associated with the degree of radiographic lateral subluxation and sagittal imbalance, and therefore may require inclusion of the lumbar deformity (lateral subluxation) as well as extensive sagittal realign- ment. With radicular pain, it is important to note whether the location of the pain is the same as that of the concav- ity. Moreover, it helps to determine if leg pain stems from central or lateral recess (entrance zone, midzone, or exit zone) stenosis or both, as the latter may require greater bone decompression and probably instrumented fusion at the area of decompression. Finally, pain can include both the lower back and the extremities, and the operative approach should be tailored accordingly. Patients are examined in their underwear and, for fe- males, bra. As patients stand with hips and knees fully extended, they are observed at an appropriate distance and any trunk shift is noted. The relationship of the patient’s head to the pelvis is also noted when evaluating overall coronal and sagittal balance. Any shoulder or pelvic asymmetry is documented. Forward and lateral bending maneuvers help assess the curve’s rigidity, which is an important factor in terms of prognosis. Leg-length discrepancy and pelvic obliquity are evaluated. When leg-length discrepancy is the likely cause of the deformity, a shoe lift is used to reevaluate the patient to see if the curve can be corrected, although such correction is unlikely in stiffer curves. A neurological examination, including all cranial nerves, motor strength, reflexes, sensory modalities, and gait, is performed. A vascular examination, using Dop- Fig. 1. Radiograph demonstrating features of fractional degenera- pler ultrasonography if needed, is performed. Sacroiliac tive lumbar scoliosis.

2 Neurosurg Focus / Volume 28 / March 2010

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC Adult degenerative scoliosis

Fig. 2. Lenke-Silva Treatment Level I. A and B: Images obtained in a 62-year-old male with neurogenic claudication. C–F: Computed tomography myelograms of L2–3, L3–4, L4–5, and L5–S1 showing spinal stenosis. G and H: Five-year postoperative radiographs demonstrating maintained alignment from L-2 to the sacrum.

Radiographic Evaluation importance as it has been correlated with successful clinical outcomes.16 Additionally, the degree of rotatory Full-length standing anteroposterior and lateral radio- 22 subluxation and olisthesis is quantified, and osteophytes graphs are obtained. Supine long cassette radiographs— are noted.22 The latter is crucial in terms of radiographic removing gravity from the trunk—are obtained if opera- mechanical stability and helps in planning the type of op- tive intervention is planned, as these images quickly show erative intervention required for a given patient. the degree of correction spontaneously occurring. These curves typically have an L2–3 apex and are associated with lateral olisthesis, rotatory subluxation, and minimal Treatment structural vertebral deformity. They tend to have lumbar Nonoperative Treatment Options hypolordosis and short reciprocating curves without significant scoliosis above the lumbar levels. A fractional Nonoperative management is started provided that curve, L-4 to the sacrum, is also typically evident (Fig. 1). there are no significant stenotic, radicular, and/or back Computed tomography myelograms and MR images are pain symptoms, including curves < 30° with < 2 mm of also obtained. The former are particularly useful in this subluxation with anterior osteophytes.13 Patients undergo- older age group, as some patients cannot undergo MR im- ing such procedures usually have reasonable sagittal and aging studies because of cardiac pacemaker placement. coronal balance. Patients are asked to get involved in a Provocative testing helps to elucidate the pain genera- low-impact muscle-strengthening endurance program. tors, which can include facet/nerve root blocks and dis- The use of nonsteroidal antiinflammatory drugs is in- cograms. Such testing helps to further determine whether stituted as needed, and based on DEXA scan findings, the structural deformity and/or the other pathologies are appropriate referral for osteopenia/porosis treatment is the primary pain generators, which in turn helps to de- requested. Epidural and/or selective nerve root injections termine the necessary portions of pathology that should are carefully considered based on clinical findings and be addressed, would best relieve the patient’s symptoms, neuroradiographic studies. Bracing really has no role in and produce a successful clinical outcome.15 Appropriate this population. It is not likely to halt curve progression, Cobb angle measurements as well as the parameters of as the mode of progression is usually not spinal growth spinopelvic balance are calculated for surgical planning. but transverse instability, and its method of temporary In this group of patients, sagittal balance is of the utmost pain relief will be outweighed by deconditioning.30 Oper-

Neurosurg Focus / Volume 28 / March 2010 3

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC F. E. Silva and L. G. Lenke ative intervention is offered to those who do not meet the TABLE 2: Patient demographics comparing Lenke-Silva above criteria, who fail conservative pain management, Treatment Level I with Level II* and/or those whose disease progresses. Treatment Treatment Indications for Operative Intervention Characteristic Level I Level II p Value Patients whose nonoperative pain management has age at surgery (yrs) 75.0 ± 6 66.3 ± 7.6 0.01 failed are considered for surgical treatment. Specific average follow-up (yrs) 4.6 ± 2.7 4.6 ± 2.4 0.39 treatment options are offered when correlation occurs be- preop curve magnitude (°) 16.0 ± 6 22.0 ± 8 0.23 tween clinical and specific radiographic findings, particularly, L-3 and L-4 endplate angulations, lumbar lordosis, postop curve change (°) 3.0 ± 4 1.0 ± 8 0.5 28 thoracolumbar kyphosis, and lateral olisthesis. Lumbar * Values are presented as mean ± SD unless otherwise indicated. curves with > 30–40° and/or 6 mm of olisthesis on presentation are also considered for operative intervention. ited decompression. Radiographically, anterior osteo- Moreover, curve progression as well as progressive neu- 25 phytes should be present with no more than 2 mm of rological deficits are indicators for surgical intervention. subluxation and reasonable sagittal/coronal balance. Ad- Patients whose curves progress more than 10° and/or have ditionally, there should be minimal or no back pain and/ an increase in subluxation > 3 mm with increasing clini- or deformity complaints, and the curve should be < 30° cal symptomatology are offered surgical options. without thoracic hyperkyphosis and/or imbalance (Fig. 2). However, decompression alone for stenosis with as- Six Levels of Operative Treatment: Lenke-Silva Treatment sociated scoliosis can lead to deformity progression and Levels I–VI worsening of symptoms. Six distinct levels of operative treatment are avail- Level II treatment involves adding instrumentation able for ASD and include the following: I, decompression limited to the area of the decompression in patients with alone; II, decompression and limited instrumented poste- the above symptoms (requiring extensive decompression) rior spinal fusion; III, decompression and lumbar curve and curves < 30°, more than 2 mm of subluxation, and no instrumented fusion; IV, decompression with anterior and anterior osteophytes in the area of decompression. Again, posterior spinal instrumented fusion; V, thoracic instru- there should be no back pain/deformity symptoms or tho- mentation and fusion extension; and VI, inclusion of os- racic hyperkyphosis in a relatively well-balanced patient teotomies for specific deformities. A matrix is presented (Fig. 3). In a series of 55 consecutive patients with ADS to help sort the patient’s symptoms and radiographs into treated using decompression alone (Level I, 16 patients) these 6 levels of treatment (Table 1). versus decompression with limited instrumented fusion Level I treatment consists of decompression alone, (Level II, 39 patients), the Level I patients were older which is usually suitable for patients with neurogenic and had smaller curves (Table 2). At a minimum 2-year claudication due to central stenosis and requiring a lim- follow-up, 62% of Level I versus 82% of Level II patients

Fig. 3. Lenke-Silva Treatment Level II. A and B: Radiographs obtained in a 73-year-old male, showing spinal stenosis from L-3 to L-5 and a rotary subluxation at L3–4. He was treated with decompression and a posterior spinal fusion from L-3 to L-5. C and D: At 4 years postoperatively, he had a solid fusion from L-3 to L-5 with slight disc degeneration at L2–3.

4 Neurosurg Focus / Volume 28 / March 2010

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC Adult degenerative scoliosis

Fig. 4. Lenke-Silva Treatment Level III. A–D: Images obtained in a 49-year-old female with degenerative lumbar scoliosis and associated back and leg pain. She underwent a T-11 to the sacrum posterior spinal fusion with TLIFs at L2–3 and L5–S1. reported a good–excellent result (p < 0.05). By 5 years increased mobility from a formal anterior approach in of follow-up, 12 of the 16 Level I patients had recurrent older patients. Hence, an ASF is selectively recommended stenosis, whereas 14 of the 39 Level II patients had ad- for patients with severe stenosis, back pain, and deformity jacent level stenosis; the stenosis rate was greater in the symptoms with mild sagittal imbalance. There should be Level I than in the Level II patients (p = 0.008) (Cheh G, no anterior osteophytes or thoracic hyperkyphosis and > Lenke LG, Bridwell KH, et al., presented at the Scoliosis 2 mm of subluxation (Fig. 5). Research Society Annual Meeting, 2006). Level V treatment involves extending the fusion and For Level III treatment, the entire lumbar curve in instrumentation into the thoracic region in patients satis- addition to the necessary decompressions is included in fying the aforementioned criteria and having thoracic hy- the instrumented fusion when symptoms of primary back perkyphosis and/or thoracic decompensation. In addition, pain are associated with the spinal deformity. Here, the those with global and/or coronal imbalance become can- clinical correlation of pain with the location of the curve didates for thoracic extension of their fusion/instrumenta- becomes very important in terms of further selecting the tion (Fig. 6). Very often, osteotomies can be particularly appropriate operative treatment. Typically, these curves useful in this subgroup of patients. are > 45°, have > 2 mm of subluxation, and lack anterior osteophytes in the operative region, although there is Osteotomy Choices: Treatment Level VI reasonable coronal and sagittal balance (Fig. 4). Anterior Patients whose deformity demonstrates > 30% correc- spinal fusion via a TLIF approach can be an important tion on bending radiographs do not require osteotomies, adjunct at the lower ends of the construct when fusing to as they are considered flexible. Curves that are corrected the lumbosacral junction. < 30% are considered stiff deformities and might require Level IV treatment consists of anterior and posterior osteotomies. However, many deformities are rigid, and fusion of the lumbar spine. Anterior spinal fusion has patients are not clinically balanced or they have already played a significant role in correcting lumbar hypokypho- undergone fusion. It is this group of patients that may also sis and imbalance. In addition, it adds indirect decom- require osteotomies, because the deformities are stuck. pression via foraminal distraction. It helps decrease pseu- Osteotomies can aid not only in clinically rebalancing darthrosis, especially in smokers, patients with diabetes, the patient, but also in decreasing the load placed on the and osteopenic patients. In the latter group, it also helps instrumentation at the metal-bone interface. Rebalancing prevent posterior instrumentation failure by load sharing, the spine is of the utmost clinical importance as a signifi- especially in obese patients. Note, however, that there is cant link has been found between it and outcomes.1 The

Neurosurg Focus / Volume 28 / March 2010 5

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC F. E. Silva and L. G. Lenke

Fig. 5. Lenke-Silva Treatment Level IV. A–D: Images obtained 59-year-old female with a 58° ADS lumbar curve who underwent a same-day L-2 to the sacrum ASF and a T-12 to the sacrum posterior spinal fusion for correction of her deformity. intelligent use of osteotomies begins with the judicious spine is flat or kyphotic. In contrast, Type II sagittal im- evaluation of both clinical and radiographic coronal and balance refers to global and segmental imbalance. When sagittal balance and is the main component of Level VI sagittal and coronal imbalance coexist, they can also be treatment. Cases of sagittal imbalance can be classified classified into Type A or7 B. With Type A imbalance, into Type I or II.7 the patient’s shoulders and pelvis are tilted in opposite Type I sagittal imbalance refers to patients who are directions. Conversely, with Type B imbalance, both the globally balanced but in whom a segmental portion of the shoulders and the pelvis tilt in the same direction. Once

Fig. 6. Lenke-Silva Treatment Level V. A and B: Images obtained in a 75-year-old female with degenerative lumbar scoliosis and associated coronal and sagittal imbalance. She underwent a posterior spinal fusion from T-2 to the sacrum and TLIFs at L4–5 and L5–S1. C and D: At 3 years postoperatively, her alignment was nicely restored and maintained. E–H: Preoperative and postoperative clinical photos demonstrating restored coronal and sagittal alignment/balance.

6 Neurosurg Focus / Volume 28 / March 2010

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC Adult degenerative scoliosis

Fig. 7. Lenke-Silva Treatment Level VI. A and B: Images obtained in a 63-year-old female with lumbar degenerative scoliosis. Two months after surgery, which was performed elsewhere, early L-5 screw pullout developed as did subsequent severe sagittal imbalance. The patient then underwent a revision posterior spinal fusion, an L-3 pedicle subtraction osteotomy, and an ASF. C and D: At 3 years postoperatively, images revealed corrected sagittal balance. E–H: Preoperative and postoperative clinical photos demonstrating excellent coronal and sagittal balance. the latter situation is recognized in the rigid spine, then should begin at a neutral and stable vertebra and should alternative options of bone resection techniques can be never end at a rotatory subluxation. One could end the fu- determined. sion at L-5; however, it must be extended to the sacrum if With Type I sagittal imbalance, Smith-Petersen os- there is an oblique take-off of L-5 on the sacrum—typical teotomies are typically indicated, provided that mobility with fractional curves > 15°—advanced degeneration of at the disc space is adequate to permit extension.29 If the the L-5/S-1 intervertebral disc, L5–S1 spondylolysis, or disc space is not sufficiently mobile but bone stock is ad- previous decompression at this segment. Additionally, fu- equate, then anterior releases with a concomitant morsel- sion at T-12 and above should be considered for extension ized graft can be used. If bone stock is inadequate, then to the ilium/S-1. Again, fractional curves > 15° must be anterior structural grafts are used. The latter can also be included in the distal fusion to achieve balance. used for Type II imbalances when Smith-Petersen osteotomies will permit the weight-bearing line to fall within 3 Complications cm of the sacrum (Fig. 7). Another alternative for Type Among spinal deformity surgeries, adult deformity II imbalance is a pedicle subtraction osteotomy, which is 3,10,32 useful when bone stock is poor as well as in smokers and corrective procedures carry a high complication rate. diabetic patients because bone-on-bone contact occurs at Often this group of patients has multiple comorbidities, the time of osteotomy closure, with high fusion rates of and the operations are more involved to achieve appropri- the vertebral body. Typically, it affords ~ 30° of lordotic ate balance and proper load sharing on the instrumenta- correction; hence, it is often suitable for global imbalance tion, the latter being particularly important in osteopenic correction without the need for anterior releases or struc- patients. Such complications include infections, CSF tural grafting.12 Anterior support may be necessary when leaks (especially among revision cases), implant failures, fusing to the sacrum, but with current techniques, this can junctional kyphosis, adjacent segment degeneration, and easily be achieved via a posterior-only approach.19 The pseudarthrosis. Systemic complications include myocar- precise amount of bone resection to achieve a balanced dial infarction, pneumonia, ileus, urinary tract infections, spine is readily calculated using simple trigonometric cal- deep venous thrombosis, and superior mesentery artery culations.23 Asymmetrical pedicle subtraction osteotomies syndrome. Blindness is a particularly ominous but an ex- are often useful in correcting Type A biplanar deformities. ceedingly rare complication. Hence, even when the ap- The more radical vertebral column resection technique is propriate techniques and postoperative care are undertak- often necessary for the rare Type B deformities.6,21 en, complications can still be somewhat high; however, the clinical outcomes appear to support such risks in ap- Fusion Levels propriately selected patients.2 A comparative chart of the Proximal fusion levels should start at a neutral and most helpful references for ADS evaluation and treatment stable vertebra, as defined by the center sacral vertical is featured in Table 3. line.8,9,20 The fusion should never stop at a rotatory subluxation. Furthermore, the thoracic physiological apex must Conclusions be avoided.5 Hence, the fusion should stop well below T-10 or well above T5–6. Similarly, distal fusion levels Demographically and clinically, ADS is a very im-

Neurosurg Focus / Volume 28 / March 2010 7

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC F. E. Silva and L. G. Lenke - - - (continued) Conclusion should undergo augmentation w/ instrumented fusion necessarily bone demineralization osteophyte difference: the latter 2, and not the former, were found to be independent predictors of de novo scoliosis relief & improvement in functional lifestyle rate requires careful preop evaluation & surgical skill; spinal instrumentation is a very important adjunct uity, lumbaruity, lordosis, & thoracolumbar kyphosis appear to correlate w/ pain development scoliosis osteotomies outweighing the benefits at theat thoracic spine, & breakdown caudal at fusion end lead to worse clinical outcomes ties; motor potential evoked recording is a mandatory monitoring modality rection of sagittal imbalance after decompressive procedures for degenerative scoliosis, patients w/ continued back pain & possible mechanical instability patients novo scoliosis w/de typically present in the 6th decade of life; progression is likely due to degenerative changes, not de novo scoliosis is becoming one of the most prevalent findings in the aging spine;vertebral index, disc index, and lateral prevalence of degenerative scoliosis in aging population is increasing; the goal is the least intervention that will provide pain this patient population presents surgical challenge; complaints of pain must be carefully investigated; the high complication although conservative care in general be may useful, evidence supporting this hypothesis is lacking radiographic criteria should be developed to guide treatment of this patient population; endplate olisthesis, and L-4 obliq L-3 lat spondylolisthesis of the apical vertebra, Harrington & disc factor, index were related to scoliosis progression relationship to the intercrestal of L-5 line, Cobb angle, & degree of apical rotation serve as valuable progression markers gold standard & cornerstone of radiographic evaluation of patients w/ deformity wide range of normal sagittal alignment, permitting more objective evaluation of hypokyphosis & lordosis often seen in excellent overall guide for evaluation of pertinent radiographic parameter used in evaluation of patients w/ deformity significant association is foundbtwn outcomes & radiographic correction; radiographic parameters should be goal of spinal fixed, decompensated spinal deformity may be safely corrected viavertebral column resection, w/ transient complication not in patients w/ fixed imbalance, pedicle subtraction osteotomy is an important adjunct;comorbidities, however, pseudarthrosis vertebral column resection is challenging & safe technique that permits a posterior-only approach of severe spinal deformi simple mathematic equations permit reliable determination of the degree of pedicle subtraction; osteotomy needed for cor overall review of generally used posterior-only osteotomies in deformity treatment - Study Design cohort tively accrued patient cohort review retrospective, case report prospective, community-based review instructional review prospective retrospective, case report retrospective, case report instructional retrospective instructional prospective, clinical trial retrospective retrospective retrospective comparative study retrospective review of prospec instructional, book chapter 14 21 15 91 24 95 60 83 35 NA NA NA NA NA† NA† 102 102 200 No. of Patients Authors & Year 1989 demographics Benner & Ehni, 1979 TABLE 3: Recommended 3: TABLE references for ADS demographics, evaluation, and treatment* Grubb 1988 al., et 2006Kobayashi al., et Ploumis 2007 al., et nonoperative treatment van Dam, 1988 Everett & Patel, 2007 naturalhistory/treatment Schwab 2002 al., et Korovessis 1994 al., et Pritchett & Bortel, 1993 radiographic evaluation Cobb, 1948 Bernhardt & Bridwell, O’Brien 2004 al., et osteotomies Ahn 2002 al., et Bradford 1997 & Tribus, Bridwell 2004 al., et Lenke et al., 2009Lenke al., et Ondra 2006 al., et Silva 2008 al., et

8 Neurosurg Focus / Volume 28 / March 2010

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC Adult degenerative scoliosis

portant entity to the deformity surgeon. An appropriate - history and workup guide treatment, differentiating the therapy for stenosis from that for a deformity. Six different levels of treatment (Lenke-Silva Treatment Levels I–VI) of increasing complexity are available to the surgeon. More specifically, these levels of treatment help to decide when to address the stenosis alone and when to include the deformity. Viable options based on clinical and radiographic stability as well as balance and revision status include nonoperative management, decompression, instrumented posterior spinal fusion, ASF, and osteotomy. Restoring lumbar lordosis and sagittal balance take precedence over scoliosis correction. Although higher complication rates are expected, a beneficial outcome in properly selected patients is also anticipated.

Disclosure Dr. Lenke was a consultant for Medtronic until January 2009, and is a patent holder with Medtronic. Author contributions to the study and manuscript preparation

Conclusion include the following. Conception and design: FE Silva. Critically revising the article: LG Lenke. Reviewed final version of the manuscript and approved it for submission: LG Lenke. Administrative/ technical/material support: LG Lenke.

Acknowledgment The authors acknowledge Jennifer Roth for her assistance in preparing this manuscript. *

References 1. Ahn UM, Ahn NU, Buchowski JM, Kebaish KM, Lee JH, Song ES, et al: Functional outcome and radiographic correction after spinal osteotomy. Spine 27:1303–1311, 2002 2. Albert TJ, Purtill J, Mesa J, McIntosh T, Balderston RA: Health outcome assessment before and after adult deformity surgery. A prospective study. Spine 20:2002–2005, 1995 3. Baron EM, Albert TJ: Medical complications of surgical treat- standing anteroposterior radiographs important avoid decompensation; certain can parameter help in deciding L-3 at to end instrumentation this at level, saving fusion levels mity surgery ment of adult spinal deformity and how to avoid them. Spine careful curve analysis, including objective evaluation of curve parameters, is essential to prevent postop decompensation; careful attention should be paid when placing instrumentation critical at vertebrae btwn deformity curves; this will help to excellent review of overall curve analysis & decision making for choosing instrumentation & fusion levels in scoliosis/defor 31 (19 Suppl):S106–S118, 2006 4. Benner B, Ehni G: Degenerative lumbar scoliosis. Spine 4: 548–552, 1979 5. Bernhardt M, Bridwell KH: Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction. Spine 14:717–721, 1989 6. Bradford DS, Tribus CB: Vertebral column resection for the treatment of rigid coronal decompensation. Spine 22:1590– 1599, 1997 Study Design 7. Bridwell KH: Adult spinal deformity revision surgery, in Heary RF, Albert TJ (eds): Spinal Deformity: The Essen- tials, ed 1. New York: Thieme, 2007, pp 240–248 retrospective instructional/review, book chapter data review 8. Bridwell KH: Selection of instrumentation and fusion levels for scoliosis: where to start and where to stop. Invited submission from the Joint Section Meeting on Disorders of the Spine 7‡ 6‡ 95

No. of and Peripheral Nerves, March 2004. J Neurosurg Spine Patients 1:1–8, 2004 9. Bridwell KH, Lenke LG: Prevention and treatment of decompensation. When can levels be saved and selective fusion be performed in idiopathic scoliosis, in Farcy JPC (ed): Complex Spinal Deformities, Spine: State of the Art Reviews, Vol. 8, No. 3. Philadelphia: Hanley and Belfus, 1994, pp 643–657 10. Bridwell KH, Lenke LG, Baldus C, Blanke K: Major intraop-

Authors & Year erative neurologic deficits in pediatric and adult spinal defor- Total of 5225 articles.Total Illustrative cases. NA = not applicable. mity patients. Incidence and etiology at one institution. Spine fusion levels Lenke & Bridwell, 1991 Bridwell 1994 & Lenke, Bridwell 2004 al., et TABLE 3: Recommended 3: TABLE references for ADS demographics, evaluation, and treatment (continued) * † ‡ 23:324–331, 1998

Neurosurg Focus / Volume 28 / March 2010 9

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC F. E. Silva and L. G. Lenke

11. Bridwell KH, Lewis SJ, Rinella A, Lenke LG, Baldus C, Measurements Manual. Memphis, TN: Medtronic Sofamor Blanke K: Pedicle subtraction osteotomy for the treatment Danek USA, 2004, pp 71–94 of fixed sagittal imbalance. Surgical technique. J Bone Joint 23. Ondra SL, Marzouk S, Koski T, Silva F, Salehi S: Mathemati- Surg Am 86-A (Suppl 1):44–50, 2004 cal calculation of pedicle subtraction osteotomy size to al- 12. Cobb JR: Outline for the study of scoliosis. Instructional low precision correction of fixed sagittal deformity. Spine course lectures. American Academy of Orthopedic Sur- 31:E973–E979, 2006 geons 5:261–275, 1948 24. Ploumis A, Transfledt EE, Denis F: Degenerative lumbar 13. Everett CR, Patel RK: A systematic literature review of nonsur- scoliosis associated with spinal stenosis. Spine J 7:428–436, gical treatment in adult scoliosis. Spine 32 (19 Suppl):S130– 2007 S134, 2007 25. Pritchett JW, Bortel DT: Degenerative symptomatic lumbar 14. Grubb SA, Lipscomb HJ, Coonrad RW: Degenerative adult scoliosis. Spine 18:700–703, 1993 onset scoliosis. Spine 13:241–245, 1988 26. Riseborough EJ: Scoliosis in adults. Curr Pract Orthop 15. Grubb SA, Lipscomb HJ, Suh PB: Results of surgical treat- Surg 7:36–55, 1977 ment of painful adult scoliosis. Spine 19:1619–1627, 1994 27. Robin GC, Span Y, Steinberg R, Makin M, Menczel J: Scolio- 16. Jackson RP, Peterson MD, McManus AC, Hales C: Compen- sis in the elderly: a follow-up study. Spine 7:355–359, 1982 satory spinopelvic balance over the hip axis and better reli- 28. Schwab FJ, Smith VA, Biserni M, Gamez L, Farcy JP, Pagala ability in measuring lordosis to the pelvic radius on standing M: Adult scoliosis: a quantitative radiographic and clinical lateral radiographs of adult volunteers and patients. Spine analysis. Spine 27:387–392, 2002 23:1750–1767, 1998 29. Silva FE, Bridwell KH, Lenke LG: Thoracic Smith-Petersen 17. Kobayashi T, Atsuta Y, Takemitsu M, Matsuno T, Takeda N: A osteotomy versus pedicle subtraction osteotomy for posteri- prospective study of de novo scoliosis in a community based cohort. Spine 31:178–182, 2006 or-only treatment of thoracic kyphosis, in Mummaneni PV, 18. Korovessis P, Piperos G, Sidiropoulos P, Dimas A: Adult idio- Lenke LG, Haid RW Jr (eds): Spinal Deformity. A Guide to pathic lumbar scoliosis. A formula for prediction of progres- Surgical Planning and Management. St. Louis, MO: Qual- sion and review of the literature. Spine 19:1926–1932, 1994 ity Medical Publishing, 2008, pp 409–28 19. Kuklo TR, Bridwell KH, Lewis SJ, Baldus C, Blanke K, Iffrig 30. van Dam BE: Nonoperative treatment of adult scoliosis. Or- TM, et al: Minimum 2-year analysis of sacropelvic fixation thop Clin North Am 19:347–351, 1988 and L5-S1 fusion using S1 and iliac screws. Spine 26:1976– 31. Vanderpool DW, James JI, Wynne-Davies R: Scoliosis in the 1983, 2001 elderly. J Bone Joint Surg Am 51:446–455, 1969 20. Lenke LG, Bridwell KH: Achieving coronal balance using 32. Williams EL: Postoperative blindness. Anesthesiol Clin Cotrel-Dubousset instrumentation (C-D.I.). 8th Proceeding North America 20:605–622, 2002 of the International Congress on Cotrel-Dubousset In- strumentation. Montpellier, France: Sauramps Medical Pub- lishers, pp 27–32, 1991 21. Lenke LG, O’Leary PT, Bridwell KH, Sides BA, Koester LA, Manuscript submitted November 13, 2009. Blanke KM: Posterior vertebral column resection for severe Accepted January 5, 2010. pediatric deformity: minimum two-year follow-up of thirty- Address correspondence to: Fernando E. Silva, M.D., Harris five consecutive patients. Spine 34:2213–2221, 2009 Methodist Fort Worth, Neurological Surgery, North Texas Neu 22. O’Brien MF, Kuklo TR, Blanke KM, Lenke LG: Adult de- rosurgical and Spine Center, 1300 West Terrell Avenue, Suite 300, formity, in Spinal Deformity Study Group Radiographic Fort Worth, Texas 76104. email: [email protected].

10 Neurosurg Focus / Volume 28 / March 2010

Unauthenticated | Downloaded 10/02/21 09:48 PM UTC