Hospital do Servidor Público Estadual, São Paulo, SP, Brazil
Introduction
The prevalence of adult spinal deformity (ASD) has tended toincrease, associated to population aging.1,2In Brazil, a recentstudy showed a prevalence of 18.5% of ASD in outpatients,reaching 28.8% in individuals over 60 years of age.3Amongthe causes of ASD, iatrogenesis is noteworthy after long lum-bar arthrodeses; other causes include deformities associatedwith multiple fractures due to bone insufficiency (osteoporo-sis), rheumatologic diseases, such as ankylosing spondylitis,or even degenerative disc disease.4
The treatment of rigid ASD is of one of the majorchallenges in spinal surgery; these are often revision pro-cedures, performed in elderly patients with comorbidities,and osteotomies are frequently required in order to achievedeformity correction.4–8Schwab et al.9described a classifi-cation system for spinal osteotomy, based on the extent ofbone resection. The greater the resection, which increases thedegree of instability, the greater the possibility in correctingthe deformity.
Thus, according to the three-column spine con-cept proposed by Denis,10osteotomies that compromise thethree-column stability have the greatest possibility of angularcorrection for the deformity.However, three-column osteotomies (3 CO) present signif-icant risks for patients, with a high incidence of potentiallyserious complications.4,6,8,11,12The vast majority of the infor-mation on complication rates and clinical outcomes of 3 COin the treatment of rigid ASD comes from studies of patientsoperated in the United States; data on 3 CO patients in Brazil isscarce. The present study is aimed at analyzing and describingdata on clinical outcome and complication rates in patientswho underwent 3 CO for the treatment of rigid ASD in a singlehealthcare service in Brazil.
Material and methods
This is a retrospective observational analysis of a prospectivedatabase that included patients who underwent 3 CO surgi-cal treatment for ASD in a single healthcare service. The datawere analyzed after approval by the Research Ethics Commit-tee of the healthcare service responsible for the study. Patientsover 18 years of age with complete data and who had com-pleted a minimum postoperative follow-up of 12 months wereincluded.Primary data were collected immediately prior to surgery,and included demographic data such as age, gender, bodymass index (BMI), and history of prior surgery, as well as clin-ical and functional assessment using the Oswestry DisabilityIndex (ODI) and the Scoliosis Research Society-22 (SRS-22),translated to and validated into Brazilian Portuguese.13,14The data referring to the surgical procedure were: type ofosteotomy (according to the classification proposed by Schwabet al.9), site of osteotomy, extent of arthrodesis (proximal anddistal fusion level), use or non-use of a screw in the iliacbone, one-time or staged surgery, total surgery time, and esti-mated blood loss. In the postoperative follow-up, clinical and
functional parameters were assessed in order to identify theclinical result obtained in the surgical procedure.
Information on any clinical and neurological complicationswas collected. Any alteration in the neurological exami-nation of the patient, upon waking or during the entirefollow-up period, was considered a neurological complicationwhen compared with findings from examination immediatelybefore the surgical procedure.
The radiographic evaluation was made using total(panoramic view) radiographs of the spine in orthostasis andfollowed a specific pattern.15The scanned images were ana-lyzed with the Surgimap Spine software (Nemaris Inc. NewYork, USA) for the measurement of the radiographic parame-ters of interest in ASD assessment: sagittal vertical axis (SVA),thoracic kyphosis (TK), lumbar lordosis (LL), pelvic version(PV), pelvic incidence (PI), and discrepancy between PI andLL (PI-LL). The recently standardized nomenclature for suchparameters in Brazilian Portuguese was adopted.1
16The pre and postoperative clinical and radiographic param-eters were compared using the paired and unpaired Student’st-test. The Shapiro–Wilk test was used to check the normal-ity of the variables. Statistical analysis was performed withStata®11 SE, and the significance level was set at 5%. Thus,results considered statistically significant had a p-value of lessthan 0.05.
Results
Ten patients with completed data were included, one manand nine women (Table 1). The mean age at surgery was 66.6years (range: 57–79 years). The mean BMI of the patients was29.5 kg/m2(range: 25.5–32.4 kg/m2). The patients were classi-fied in accordance with the SRS-Schwab classification17: seven(70%) had no coronal plane deformity (type N), two (20%) hada lumbar deformity (type L), and one (10%) had a double curve(type D). As for the sagittal modifiers, all patients had at least“+” for the three modifiers (SVA, PV, and PI-LL). Only onepatient did not have a history of previous surgery; the mean ofthe sample was 1.6 prior surgical procedures, ranging from 1to 3. The mean follow-up time was 24 months (range: 14–34).One patient died in the perioperative period; her postoperativedata were not considered.Table 2 shows the pre and postoperative values of the radio-graphic parameters. A statistically significant improvement
was observed in all parameters considered (SVA, PV, LL, andPI-LL; p ≤ 0.001). Regarding clinical features (Table 3), a sig-nificant improvement was observed in the ODI and SRS-22total scores, and in the Function/Activity, Pain, and Appear-ance domains (p < 0.003). A trend toward improvement wasobserved in the SRS-22 Mental Health domain score, albeit notsignificant (p = 0.080).
Table 4 presents data on surgical procedures. Threepatients (30%) had one stage surgery, while six (60%) hadtwo stages, and one (10%), three stages. The mean time ofsurgery (considering the sum of the surgical times in casesof more than one surgery) was 505 min (392–640), signifi-cantly higher in patients undergoing staged surgery thanin those undergoing only one surgery (549.3 min ± 58.6 minvs. 403.3 min ± 9.9 min, p = 0.003). The mean estimated bloodloss was 3630 ml (2600–4600 ml), also considering the sum
of the surgical times in cases of more than one surgery.There was a trend toward greater estimated blood lossin patients who underwent staged surgery than in thosewho underwent only one surgery, but it was not signifi-cant (3914.3 ml ± 651.7 ml vs. 2966.7 ml ± 472.6 ml, p = 0.055).Regarding the type of osteotomy, one (10%) patient under-went grade 5 osteotomy (Fig. 1), corresponding to vertebralcolumn resection (VCR); four (40%), grade 4 osteotomy(Fig. 2), corresponding to pedicle subtraction osteotomyextended to the resection of the vertebral plateau and supe-rior intervertebral disc; and five (50%), grade 3 osteotomy,conventional pedicle subtraction. Grade 5 osteotomy (VCR)was performed at T12 level, and all pedicle subtractionosteotomies, both grade 3 and 4, were performed at L3level. The mean lumbar lordosis gain in patients who under-went pedicle subtraction osteotomy was 34.2?, ranging from25?to 46?.
Considering the level of fusion, T10 was the proximal levelin six patients (60%) and T4 in four (40%). Regarding the dis-tal level, all patients (100%) had sacrum involvement; nine(90%) with fixation to the iliac and one (10%) without. In allpatients (100%) with iliac fixation, the S2 alar-iliac techniquewas used.18In three patients (30%), two rods that crossed thelevel of osteotomy were used; in one (10%), three rods, and insix (60%), four rods were used.Six (60%) patients had at least one complication, in atotal of ten events, with a mean of one complication perpatient. Three (30%) patients woke up from surgery with somedegree of reduction in motor strength in the lower limbs com-pared to the preoperative state; two recovered and one didnot.
Four (40%) presented surgical wound complications, be itdehiscence or infection, and all required a second surgical pro-cedure, with a mean of 1.7 procedures per patient. One (10%)patient evolved with proximal junctional kyphosis deformity>10?(considering the angle measured between the most prox-imal instrumented vertebrae and two levels above), but thepatient had no related complaints and did not undergo anyother surgical procedure. One case of pulmonary thromboem-bolism was observed, and managed with drug treatment. One(10%) patient died on the 23rd day of hospitalization due tocomplications. The mean number of hospitalization days was23.3, ranging from seven to 61. The incidence of complicationswas similar between patients submitted to staged surgery andonly one surgery (p = 0.849).
Discussion
The global aging of the population is associated with anincreased prevalence of age-related health problems, includ-ing spinal deformity. It has recently been shown that theimpact of spinal deformity on patients’ quality of life is compa-rable to that of other chronic diseases such as pneumopathies,diabetes, and cardiopathy.19,20
Thus, an increase in the num-ber of ASD correction procedures is to be expected. Theseprocedures often require the use of osteotomies, especiallyin rigid deformities,5,6,8and are often associated with compli-cations. Publications have shown that patients undergoing 3CO are subject to even greater risks of complications, includ-ing neurological deficits.12Thus, the present study presenteda series of patients who underwent 3 CO for ASD correction,analyzing the patients’ profile, details of the surgery, the cor-rection of radiographic parameters, clinical outcomes, andcomplications in these patients.The patients were classified by the SRS-Schwab system,and the majority presented no deformity in the coronal plane(Type N). In the study that proved the clinical relevance ofthe SRS-Schwab classification,21it was observed that the inci-dence of patients with Type N deformity was lower than thatof those with coronal deformities, but patients with Type Ndeformity had a significantly higher incidence of surgery andmore frequently needed osteotomies. The fact that the presentstudy included only patients who underwent surgery and 3CO explains the vast majority of cases classified as Type N.Regarding the sagittal modifiers, all patients in the presentstudy presented alterations in the three modifiers, which isalso in agreement with the literature; patients who undergosurgery have worse sagittal modifiers; the worse these modi-fiers, the more frequent the need for osteotomies.213 CO is a technique with high corrective possibility fordeformities in the sagittal plane and coronal plane, or inboth.5,6However, due to the high morbidity associated withthis procedure, its indication should be restricted to casesin which there is severe global sagittal disequilibrium and/orrigid deformities, often in patients with long arthrodesed seg-ments of the spine.22All but one patient, in this 3 CO study,had previously been submitted to surgery on some segmentfor lumbar arthrodesis. Although the present study consid-ered patients with rigid deformity, a high deformity correction
possibility was observed. A significant improvement in allradiographic parameters considered was noted, and the meangain of lumbar lordosis was 34.2?in patients who underwentpedicle subtraction. The literature indicates that a pediclesubtraction osteotomy has a correction possibility between25?and 35?.9,23–25In addition to presenting even greater pos-sibility in correcting rigid deformities of the spine, grade 5osteotomy (VCR) is indicated when there is a concomitantimbalance in the sagittal and coronal planes.23A grade 5osteotomy was performed in one patient, classified as SRS-Schwab type D, SVA+, PT++, PI-LL +, who had, in additionto sagittal imbalance and a lumbar curve of 68?in a previ-ously arthrodesed region, a thoracic curve of 35?and coronalimbalance. After surgery, the coronal deformity was correctedto 13?(correction of 55?, 80%), in addition a 9.1 cm SVAcorrection.
The occurrence of complications in 60% of the patients(6/10), with a mean of one complication/patient, reinforcesthe high morbidity and complexity of the treatment of ASDwith 3 CO described in the literature, with rates of up to82%.5,7,13,23,26,27Recently, Kelly et al.12presented the resultsof a multicentric retrospective analysis of complications in3 CO surgeries, considering this technique by the main spe-cialists in the United States, and demonstrated complicationsin 50.8% of the patients. Regarding the occurrence of neuro-logical complications, Lenke et al.27presented a prospectivemulticenter study in which they evaluated the neurologicaloutcome in patients undergoing surgical treatment for com-plex ASD, 79% of whom underwent 3 CO. It was observed that,at the time of discharge, 22.18% of the patients presented somelevel of loss of strength in the lower limbs and, after sixthmonths, 10.82% persisted with some loss of strength in thelower limbs. In the present study, three (30%) of the patientspresented some degree of loss of strength in the lower limbsand only one (10%) maintained this loss in the postoperativefollow-up.
Among the most frequently described complications ispseudarthrosis, followed by implant rupture.5,24,28However,in the present study, no patient presented implant ruptureor clinical or radiological suspicion of pseudoarthrosis, witha mean follow-up of 24 months (minimum of 14). The use ofmultiple-rod constructs crossing the 3 CO site has been rec-ommended to increase stability, and to prevent implant failureand the occurrence of pseudarthrosis.28More recently, Guptaet al.29showed that in addition to the number of rods cross-ing the 3 CO site, the fact that the third or fourth rod wasindependent (satellite rod), i.e., not connected to the primaryrods, presented a significantly lower rate of implant failureand/or pseudarthrosis. In the present study, in most cases the3 CO site was crossed by two or more rods; in all cases, therods were “satellites”, without connection to the primary rods,which may have had a protective effect against complicationsrelated to implant failure.
recent study demonstrated the benefits of surgery overconservative treatment in clinical improvement and consid-ered indicators of quality of life for patients with ASD.30Studies have shown that even patients with clinical and/orsurgical complications, including those requiring reoperation,presented improved quality of life indicators after 3 CO.11,24The present study demonstrated a significant improvementin quality of life indicators, even with a complication rate of60% of the cases.The main limitation of the present study is the small sam-ple size analyzed and the fact that patients from only onehealthcare service were included, which reduces the possi-bility of statistical analysis. However, this study presenteddata that considered patients submitted to the complex 3CO surgical procedure, with a minimum of 12 months post-operative follow-up, considering the structure of a Brazilianhealth service, data still little reported in our midst. One ofthe purposes of the present study is to raise interest in otherhealthcare services for the development of multicentric anal-yses, increase sample size, and improve the possibility forinterpretation of data.
Conclusion
Despite the high rate of complications, 3 CO was shown to be asuccessful technique considering the clinical and radiographicresults in the treatment of complex cases of rigid ASD in asample of patients operated in a Brazilian healthcare service,with a minimum of 12 months follow-up.
Conflicts of interest
The authors declare no conflicts of interest.
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