Multilevel Surgery Research Articles

Systematic review and updated meta-analysis of multi-level surgery for patients with OSA

ObjectivesTo perform an updated systematic review for determining the surgical success rate of multilevel upper airway surgery for patients with obstructive sleep apnea/hypopnea syndrome (OSA). MethodsA systematic review was performed to identify English-language studies that evaluated the treatment of adult OSA patients with multilevel OSA surgery up to January, 2018. We used polysomnography as a metric of treatment success. Articles were only included if the surgery intervention involved at least two of the frequently involved anatomic sites: nose, oropharynx and hypopharynx. Eighty-seven studies fit the inclusion criteria and a meta-analysis was performed to determine the overall success. ResultsThe meta-analysis included 3931 subjects with a mean age of 46.1 years. The originally reported success rate in the included literature was 59.9%. A meta-analysis was performed to redefine the success rate to be consistent with the commonly agreed upon criteria - namely “a reduction in apnea/hypopnea index (AHI, /hr.) of 50% or more and an AHI of less than 20”. The recalculated success rate was 60.2%. Standard meta-analytic techniques for combining p-values between studies after weighting for sample size found significant improvements in AHI, apnea index, % of rapid eye movement sleep, lowest saturation of oxygen (%), and Epworth Sleepiness Scale. ConclusionThis study shows the significant improvement of treatment outcomes with multilevel surgery for OSA patients.

Incidence and risk factors for prolonged postoperative opioid use following lumbar spine surgery: a cohort study.

Sustained postoperative opioid use after elective surgery is a matter of growing concern. Herein, the authors investigated incidence and predictors of long-term opioid use among patients undergoing elective lumbar spine surgery, especially as a function of opioid prescribing practices at postoperative discharge (dose in morphine milligram equivalents [MMEs] and type of opioid). The OptumLabs Data Warehouse (OLDW) was queried for postdischarge opioid prescriptions for patients undergoing elective lumbar decompression and discectomy (LDD) or posterior lumbar fusion (PLF) for degenerative spine disease. Only patients who received an opioid prescription at postoperative discharge and those who had a minimum of 180 days of insurance coverage prior to surgery and 180 days after surgery were included. Opioid-naive patients were defined as those who had no opioid fills in 180 days prior to surgery. The following patterns of long-term postoperative use were investigated: additional fills (at least one opioid fill 90-180 days after surgery), persistent fills (any span of opioid use starting in the 180 days after surgery and lasting at least 90 days), and Consortium to Study Opioid Risks and Trends (CONSORT) criteria for persistent use (episodes of opioid prescribing lasting longer than 90 days and 120 or more total days' supply or 10 or more prescriptions in 180 days after the index fill). Multivariable logistic regression was performed to identify predictors of long-term use. A total of 25,587 patients were included, of whom 52.7% underwent PLF (n = 13,486) and 32.5% (n = 8312) were opioid-naive prior to surgery. The rates of additional fills, persistent fills, and CONSORT use were 47%, 30%, and 23%, respectively, after PLF and 35.4%, 19%, and 14.2%, respectively, after LDD. The rates among opioid-naive patients were 18.9%, 5.6%, and 2.5% respectively, after PLF and 13.3%, 2.0%, and 0.8%, respectively, after LDD. Using multivariable logistic regression, the following were identified to be significantly associated with higher risk of long-term opioid use following PLF: discharge opioid prescription ≥ 500 MMEs, prescription of a long-acting opioid, female sex, multilevel surgery, and comorbidities such as depression and drug abuse (all p < 0.05). Elderly (age ≥ 65 years) and opioid-naive patients were found to be at lower risk (all p < 0.05). Similar results were obtained on analysis for LDD with the following significant additional risk factors identified: discharge opioid prescription ≥ 400 MMEs, prescription of tramadol alone at discharge, and inpatient surgery (all p < 0.05). In an analysis of pharmacy claims from a national insurance database, the authors identified incidence and predictors of long-term opioid use after elective lumbar spine surgery.

Incidence, risk factors, and treatment of incidental durotomy during decompression in degenerative lumbar spine conditions.

The purpose of this study was to identify independent risk factors for incidental durotomy (ID) during decompressive lumbar spine surgery, and to describe its treatment. This retrospective review includes 650 patients who underwent lumbar decompression at a tertiary institution between January 2015 and October 2019. Data collection was obtained through one independent researcher. The incidence rate and treatment of ID was evaluated by a chart review of operative notes, patient charts, physiotherapy reports, and nursing reports. The incidence rate of ID was 12.6%. The most common reason for admission was disc herniation (63.2%), followed by vertebral stenosis (22.1%). ID resulted in significantly longer operation time (P=0.0001) and length of hospitalization (P=0.0001). A correlation between ID and patient's diagnosis (P=0.0078) as well as the chosen type of surgery (P=0.0404) with an Odds Ratio to cause ID of 1.9 for laminectomy and 1.6 for undercutting compared to microdiscectomy were found. However, age, sex, surgeon experience, lumbar level, revision surgery, as well as multilevel surgery were not significantly correlated with the incidence of ID. Dural tears were closed with dural sealant (47.2%), polyester 4-0 sutures (11.1%) or a combination of both (37.5%) and the majority of patients had bed rest of at least two days. By usage of these treatment methods no patient needed reoperation. Diagnosis of vertebrostenosis as well as laminectomy were significantly correlated with the incidence of ID. Treatment with intraoperative closure and postoperative bed rest even though not standardized led to complication free outcomes.

The safety and short-term efficacy of modified lateral pharyngoplasty combined with multilevel surgery for OSA

Objective:To explore the safety and short-term efficiency of modified lateral pharyngoplasty combined with surgeries in other sites including nose and tongue. Methods:Thirty-five patients with OSA confirmed with polysomnography received modified lateral pharyngoplasty under general anesthesia. Some of the patients may also receive glossopharyngeal or nasal surgeries according to their physical examination, Müller test with electronic nasolaryngology and polysmnography. The postoperativepain, capacities of swallowing and speaking, and related postoperative complications after surgeries were recorded. And the changes of epworth sleep scale （ESS） snoring sore, apnea and hypopnea index （AHI） and lowest oxygen saturation （LSaO2） were compared before and after surgeries. Results:Among the 35 patients, 1 patient experienced experienced dyspnea after extubation and 2 patients experienced postoperative bleeding. The mean VAS after 1, 4 and 7 days of the surgery were 5.41±2.42, 2.93±1.80, 2.91±1.26, respectively. The mean pain visual analogue scale（VAS） was 5.41±2.42, 2.93±1.80 and 2.91±1.26 on the 1st, 4th and 7th day after operation. The mean time of starting to eat liquid and semi-liquid were （3.23±2.11） dand （5.55±2.67） d after surgery, respectively. Twenty-eight patients underwent 3-6 months follow-up, there was no significant difference in body mass index （BMI） before and after surgery, while mean ESS and snore index were significantly improved, ESS decreased from 11.33±4.91 to 6.19±4.45, and snore index decreased from 6.93±2.23 to 1.25±1.96. Among them, 23 of patients those patients received polysomnography after surgeries, AHI, LSaO2 and time with oxygen saturation below 90% （CT90） were significantly improvement. The mean AHI decreased from 45.05±27.90/h to 18.61±20.85/h，and mean SaO2 increased from 71.17% to 80.87%. Conclusion:Modified lateral pharyngoplasty combined with selective nasal and lingual plane surgery in the treatment of OSA is safe and can significantly improve ESS, snoring, AHI， LSaO2and other indicators.Modified lateral pharyngoplasty selectively with surgeries of nose or tongue is a kind of safe and effective surgery to treat OSA that ESS, snoring, AHI and SaO2can have satisfactory improvement.

Variables predictive of surgical outcomes after hyoid myotomy with suspension to thyroid cartilage

ObjectivesTo evaluate variables predicting improvement in obstructive sleep apnea (OSA) with hyoid suspension to thyroid cartilage 4-suture technique. MethodsSixty adult patients (age range 23–78 years) with OSA underwent hyoid suspension to thyroid cartilage with or without concurrent multi-level surgery over an eight-year period from 2011 to 2019 at a tertiary academic center. All patients had a preoperative apnea hypopnea index (AHI) ≥ 5. Changes in mean AHI, Epworth Sleepiness Scale (ESS), and lowest oxygen saturation (LSAT) were measured with paired Student t-test. Linear and logistic regression models were used to predict change in AHI and surgical success respectively with respect to body mass index (BMI), age, sex, previous sleep surgery, concurrent retrolingual surgery, concurrent palatopharyngoplasty, and preoperative AHI. ResultsThe mean AHI demonstrated a significant improvement from a preoperative AHI of 39.0 ± 25.5 to a postoperative AHI of 31.2 ± 23.4 (p = 0.005). The mean Epworth Sleepiness Score (ESS) significantly improved from 13.1 ± 6.0 to 9.2 ± 5.7 (p = 0.000012). Surgical success, defined as a 50% reduction in preoperative AHI to a postoperative AHI ≤ 20, was obtained in 18/60 (30.0%) patients. Preoperative BMI significantly correlates with variation of change in AHI in multivariable linear regression model (p = 0.003). Preoperative AHI was significant predictor of surgical success in multivariable logistic regression model. ConclusionThe magnitude of improvement in polysomnographic parameters after hyoid suspension to thyroid appears to be more significant in patients with lower BMI. Even patients with an obese BMI and severe OSA achieve significant improvement from this procedure.

One-Stage Multilevel Surgery for Treatment of Obstructive Sleep Apnea Syndrome.

We report the results of one-stage multilevel upper airway surgery for patients who could not tolerate continuous positive airway pressure (CPAP). Patients treated with multilevel surgery at a University Hospital in 2015–2019 were identified from a prospectively maintained database. The inclusion criteria were aged 18–70 years, body mass index (BMI) < 35 kg/m2, apnea–hypopnea index (AHI) > 20, and lingual tonsil hypertrophy grade 3 or 4. Drug-induced sleep endoscopy was performed before surgery in all patients. Multilevel surgery was performed in one stage and included expansion sphincter pharyngoplasty (ESP), coblation tongue base reduction (CTBR), and partial epiglottectomy (PE) as required. The outcome measures were postoperative AHI, time percentage oxygen saturation < 90%, and Epworth Sleepiness Scale (ESS) score. A total of 24 patients were included: median age 49.1 years, average BMI 27.26 kg/m2, and 90% men. Ten patients received ESP plus CTBR plus PE, eight received ESP plus CTBR, and six received ESP plus PE. The mean preoperative AHI was 33.01 at baseline and improved to 17.7 ± 13 after surgery (p < 0.05). The ESS score decreased from 11 ± 5.11 to 7.9 ± 4.94 (p < 0.05). The surgical success rate according to Sher’s criteria was 82.3%. The median follow-up was 23.3 months (range 12–36). These findings suggest that multilevel surgery is a safe and successful treatment of OSAHS.

Comparative Efficacy of Patients with OSA Undergoing Multi-level Surgery followed by Upper Airway Stimulation vs. Isolated Upper Airway Stimulation

PurposeUpper airway stimulation (UAS) via hypoglossal nerve stimulation is a viable management option for patients with obstructive sleep apnea (OSA). Important exclusion criteria for the current UAS protocol include AHI above 65 events per hour or concentric collapse of the velum seen on drug-induced sedation endoscopy (DISE). The authors describe the treatment efficacy of a cohort of UAS patients who were initially ineligible, but who were implanted following multilevel surgery that reversed the exclusion criteria. MethodsThe design in a single-center, retrospective study. Data collection included demographics, body-mass index (BMI), apnea-hypopnea index (AHI) titration results, oxygen desaturation index (ODI), Drug Induced Sedation Endoscopy (DISE) results, Epworth sleepiness score (ESS), and Fatigue Severity Score (FSS). ResultsThirty-six subjects underwent UAS implantation (Inspire system, MN, USA) from 2016 to 2019. Eighteen subjects who were initially ineligible for UAS first underwent multi-level surgery, including uvulopalatopharyngoplasty (UPPP), genioglossus advancement (GGA), distraction osteogenesis maxillary expansion (DOME), or maxillomandibular advancement (MMA). Mean subject age was 62.3±9 years with 28% being female. Mean subject BMI was 29±4kg/m2. Seventeen subjects met the criteria for UAS and underwent surgery. Mean subject age was 62.9±14 years with 12% being female. Mean subject BMI was 26.7±4kg/m2. Mean pre-treatment AHI for 2-staged patients was 49±29 events per hour, which was reduced to 3.6±5 events per hour with an average voltage of 1.8V±0.9. Mean pre-treatment AHI for UAS-only cohort was reduced from 33±14 events per hour to 5.3±6 events per hour with an average voltage of 1.9V±0.3. ConclusionFor patients who are ineligible for UAS due to severity of OSA or concentric collapse of the velum, multilevel surgery including UPPP, GGA, DOME, or MMA followed by UAS confers reliable, effective, and equitable post-treatment results.

Bilateral C5 Palsy Following A Circumferential Surgery for Cervical Spondylotic Myelopathy: A Case Report and Review

Background and Importance: The development of C5 root palsy is a well-known potential complication of cervical spine surgeries for the correction of cervical spondylotic myelopathy. It typically occurs unilaterally, but on extremely rare occasions, bilaterally. The value of intraoperative neurophysiologic monitoring in detecting iatrogenic acute versus delayed onset C5 palsy, the rarity of bilateral C5 palsy, and its optimal management require further discussion. Case Presentation: A 49-year-old woman with quadriparesis due to cervical spondylotic myelopathy is presented. She underwent circumferential 360° cervical spine surgery. This operation was subsequently complicated by a delayed bilateral C5 palsy, despite normal transcranial motor evoked potentials (MEPs). With the utilization of conservative treatment, the complete resolution of this complication took roughly eight months. Conclusion: Bilateral C5 palsy is an infrequent consequence of multilevel cervical spine surgeries. Although intraoperative monitoring of transcranial electrical stimulation-induced MEPs has high sensitivity and specificity in foreseeing the acute-onset C5 palsy, it cannot predict delayed-onset palsy. Including the current case, only seven cases have been reported in the medical literature. Overall, conservative management in adherence to rigorous physical therapy may be an acceptable treatment.

Rates of early complications and mortality in patients older than 80 years of age after surgical treatment of acute traumatic spinal fractures: ankylosing spondylitis versus osteoporosis.

The purpose of this retrospective cohort study was to analyze the early complications and mortality associated with multilevel spine surgery for unstable fractures in patients older than 80 years of age with ankylosing spondylitis and to compare the results with an age- and sex-matched cohort of patients with unstable osteoporotic fractures. A retrospective review of the electronic medical records at a single institution was conducted between January 2014 and December 2019. Patient demographics, surgical characteristics, complications, hospital course, and 90-day mortality were collected. Comorbidities were stratified using the age-adjusted Charlson Comorbidity Index (CCI). Among 11,361 surgically treated patients, 22 patients with ankylosing spondylitis (AS group) and 24 patients with osteoporosis (OS group) were identified. The mean ages were 83.1 ± 3.1 years and 83.2 ± 2.6 years, respectively. A significant difference in the mean CCI score was found (7.6 vs 5.6; p < 0.001). Multilevel posterior fusion procedures were conducted in all patients, with 6.7 ± 1.4 fused levels in the AS group and 7.1 ± 1.1 levels fused in the OS group (p > 0.05). Major complications developed in 10 patients (45%) in the AS group compared with 4 patients (17%) in the OS group (p < 0.05). The 90-day mortality was 36% in the AS group compared with 0% in the OS group (p < 0.001). Patients older than 80 years of age with AS bear a high risk of adverse events after multilevel spinal fusion procedures. The high morbidity and 90-day mortality should be clearly discussed and carefully weighed against surgical treatment.

Perioperative Antibiotic Use in Sleep Surgery: Clinical Relevance.

Upper airway surgery is a common therapeutic approach recommended for patients with obstructive sleep apnea (OSA) to decrease disease burden. We aimed to evaluate the effect of perioperative antibiotic prescription on complication rates. Retrospective cohort (national database). Tertiary referral center. This is a retrospective study of a large national health care insurance database (Truven MarketScan) from 2007 to 2015. Subjects diagnosed with OSA who had uvulopalatopharyngoplasty (UPPP) were included and stratified in single versus multilevel surgery. Other variables included smoking, age, sex, antibiotic prescription, and comorbidities based on the Elixhauser index. Evaluated outcomes were postoperative bleeding, intubation, pneumonia, superficial surgical site infection, tracheostomy, and hospital readmission. A multivariate regression model was created to assess each complication. A total of 5,798,528 subjects received a diagnosis of OSA, of which 39,916 were >18 years old and underwent UPPP, either alone or with additional procedures. The mean age was 43 years, and 73.4% were male. Antibiotic prescription was associated with less bleeding in UPPP alone, UPPP with nasal surgery, and UPPP with nasal and tongue surgery (P < .001, P < .001, and P = .006, respectively). It was also associated with a lower prevalence of surgical site infection, pneumonia, tracheostomy, intubation, and hospital readmission (P < .001). On a multivariate model, antibiotic prescription was significantly associated with a decreased rate of complications. Although former studies recommended against the use of antibiotics after tonsillectomy, our results suggest that antibiotic prescription after UPPP for OSA was associated with less bleeding, surgical site infection, pneumonia, intubation, tracheostomy, and hospital readmission 30 days postoperatively.

The Impact of Patellar Tendon Advancement on Knee Joint Moment and Muscle Forces in Patients with Cerebral Palsy.

Background: Patellar tendon advancement (PTA) is performed for the treatment of crouch gait in patients with cerebral palsy (CP). In this study, we aimed to determine the influence of PTA in the context of single-event multilevel surgery (SEMLS) on knee joint moment and muscle forces through musculoskeletal modeling; Methods: Gait data of children with CP and crouch gait were retrospectively analyzed. Patients were included if they had a SEMLS with a PTA (PTA group, n = 18) and a SEMLS without a PTA (NoPTA group, n = 18). A musculoskeletal model was used to calculate the pre- and postoperative knee joint moments and muscle forces; Results: Knee extensor moment increased in the PTA group postoperatively (p = 0.016), but there was no statistically significant change in the NoPTA group (p > 0.05). The quadriceps muscle forces increased for the PTA group (p = 0.034), while there was no difference in the NoPTA group (p > 0.05). The hamstring muscle forces increased in the PTA group (p = 0.039), while there was no difference in the NoPTA group (p > 0.05); Conclusions: PTA was found to be an effective surgery for the treatment of crouch gait. It contributes to improving knee extensor moment, decreasing knee flexor moment, and enhancing the quadriceps and hamstring muscle forces postoperatively.

Comparison of surgical outcomes of sleep surgeries preoperatively evaluated with drug-induced sleep endoscopy and Müller's maneuver

Objective The purpose of this study was to compare surgical outcomes for obstructive sleep apnea (OSA) when the procedure was based on the results of drug-induced sleep endoscopy (DISE) vs. the awake Müller's maneuver (MM).Methods Forty-seven patients with OSA who underwent sleep surgery were included. Patients were divided into 2 groups according to their preoperative upper airway evaluation method. Twenty-five patients received only MM for surgical decision making (MM group), and 22 patients received both MM and DISE (DISE group) for surgical decision making.Results The surgical success rate of the DISE group was higher than that of the MM group (59% vs. 36%), but the difference was not significant (p = 0.118). The differences between pre- and postoperative apnea-hypopnea index (AHI) values in both the MM and DISE group were highly significantly different (p < 0.001). Fifteen patients in the DISE group (68.2%) received multi-level surgery, while in the MM group only 7 patients (28%) received multi-level surgery. Patients with more severe OSA (AHI > 22 or lowest O2 saturation < 81%) had better surgical outcomes when their surgical procedures were based on the findings of DISE, rather than those of MM.Conclusion The results indicate that DISE provides no benefits with respect to surgical outcomes for patients with mild to moderate OSA; however, for patients with more severe OSA surgical procedures based on DISE result in better outcomes.

Biomechanical assessment of patellar tendon advancement in patients with cerebral palsy and crouch gait

BackgroundPatellar height is a valuable measure to evaluate the effect of patellar tendon advancement (PTA) on knee function. In the literature, there is no validated procedure to measure the patellar height. In this study we aimed to (1) determine the patella position through musculoskeletal modeling, (2) investigate the effects of two surgical procedures applied for PTA, and (3) assess the effect of PTA in combination with single-event multilevel surgery (SEMLS) on the knee kinematics of patients with cerebral palsy (CP) and crouch gait. MethodThree-dimensional gait and X-ray data of children with CP and crouch gait were retrospectively analyzed if they had received a SEMLS in combination with PTA (PTA group, n = 18) or without PTA (NoPTA group, n = 18). A computational musculoskeletal model was used to quantify patella position, knee extension moment arm, and knee kinematics pre- and postoperatively. ResultsPatellar height significantly decreased in the PTA group (P = 0.004), while there was no difference in the NoPTA group (P > 0.05). The bony procedure for PTA provided a better Insall–Salvati ratio than the soft tissue procedure. The peak knee extension moment arm significantly increased in the PTA group (P = 0.008). In terms of postoperative knee joint kinematics, the PTA group was closer to typically developed children than the NoPTA group. ConclusionMusculoskeletal modeling was found to be an effective tool for the determination of the patellar height. PTA improved the patella position, knee extension moment arm, and knee kinematics and was an effective procedure for the surgical management of crouch gait in patients with CP.

Rehabilitation After Single-Event Multilevel Surgery for Children and Young Adults With Cerebral Palsy: A Systematic Review.

This review sought to describe and analyze published protocols for rehabilitation after single-event multilevel surgery for people with cerebral palsy, to identify their differences and limits, and to introduce a common step-by-step framework for future descriptions and assessments of postoperative rehabilitation protocols.The MEDLINE, Embase, CINAHL, and the Cochrane Library databases were searched. Inclusion criteria were as follows: (1) single-event multilevel surgery, (2) full-text reports published after 1985, and (3) articles with a method section describing the rehabilitation protocol. Interventions were coded using the Oxford Levels of Evidence and the Methodological Index for Non-Randomized Studies Index.Twenty-four articles were included in the review. Studies included patients aged 4-30 yrs with spastic cerebral palsy (hemiplegia, diplegia, and quadriplegia). The mean postoperative rehabilitation duration was 4.5 mos, with 4 sessions per week, and rehabilitation took place in a rehabilitation center. This review provides relevant information about the modalities, contents, limits, and difficulties associated with the post-SEMS rehabilitation protocol reported in the literature. Pain was identified as a major problem.A more precise and comprehensive description of post-SEMS rehabilitation protocols would be useful. The proposed five-step framework could be used by future studies to standardize their protocol description in terms of objective, content, and intensity.

84. Surgeon specialty effect on early outcomes of elective anterior cervical discectomy and fusion: an updated propensity matched and subgroup analysis of 10,116 patients

<h3>BACKGROUND CONTEXT</h3> Comparative effectiveness research has a vital role in health reform and policies. Specialty training is one of these provider-side variables and surgeons who were trained in different specialties may have different outcomes upon performing the same procedure. <h3>PURPOSE</h3> To investigate the impact of spine surgeon specialty on early perioperative outcome of anterior cervical discectomy and fusion (ACDF). <h3>STUDY DESIGN/SETTING</h3> Retrospective, 1:1 propensity score-matched cohort study. <h3>PATIENT SAMPLE</h3> A total of 21,211 patients who underwent ACDF between 2016-2018 were reviewed from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. <h3>OUTCOME MEASURES</h3> Outcomes included 30-day perioperative morbidity and mortality measures that are predefined in the ACS-NSQIP database. <h3>METHODS</h3> Patients were stratified by the specialty of surgeon performing the procedure (neurosurgery vs orthopedic surgery), and the number of levels operated on (single- vs multi-level surgery) <h3>RESULTS</h3> Patients operated on by neurosurgeons were more likely to be older, smokers, of Hispanic ethnicity, functionally dependent, and to have higher BMI, an ASA class 3 or more, baseline dyspnea, bleeding disorders, and myelopathy. In both groups (single/multi-level ACDF), cases in the orthopedic surgery cohort were more likely to have shorter operation time (104 vs 133 minutes/ 138 vs 164 minutes), longer total hospital stay (41 vs 24 hours/ 46 vs 25 hours), higher return to operating room rates within the same admission (2.1% vs 0.7%/ 2.4% vs 0.6%), be discharged to destination other than home (4.6% vs 1.2%/ 4.9% vs 1.0%), be discharged after postoperative day 1 (11.9% vs 6.7%/ 18.9% vs 10.1%), higher perioperative blood transfusion rate (2.1% vs 0.4%/ 3.1% vs 0.6%) and higher sepsis rates (0.7% vs 0.2%/ 0.7% vs 0.1%). In the single-level ACDF group, cases in the orthopedic surgery cohort had higher readmission (4.1% vs 1.9%) and unplanned intubation rates (1.1% vs 0.1%). Other outcome measures and mortality rates were similar among the cohorts. <h3>CONCLUSIONS</h3> Significant differences in early perioperative outcomes of patients undergoing ACDF by neurosurgeons and orthopedic surgeons were noted. These differences have significant clinical and cost implications for patients, physicians, payors and health systems. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

165. Risk of revision surgery following cervical disc replacement vs anterior cervical discectomy and fusion: population based cohort study

<h3>BACKGROUND CONTEXT</h3> In recent years, cervical disc replacement (CDR) has gained popularity for cervical degenerative disorders. The rationale for CDR over anterior cervical discectomy and fusion (ACDF) is preservation of segmental motion and physiological spinal kinematics, which is hoped to delay development of adjacent segment disease and reoperation rates. Superiority of CDR over ACDF in rates of secondary surgeries has not been demonstrated in long-term follow-up. <h3>PURPOSE</h3> This study compares rate of reoperation in CDR and ACDF for treatment of cervical degenerative disc disease using population-based data for the province of Ontario. <h3>STUDY DESIGN/SETTING</h3> A population-based cohort study was conducted using health administrative databases including patients undergoing ACDF or CDR between October 2005 to March 2018. <h3>PATIENT SAMPLE</h3> Patients receiving CDR vs ACDF were identified using physician service claims and hospital discharge abstracts. <h3>OUTCOME MEASURES</h3> The primary outcome was revision surgery in the cervical spine defined as an operation more than 30 days after the index procedure. Secondary outcomes were immediate/acute complications within the first 30 days after the index operation, readmissions and length of hospital stay. <b>METHODS:</b> Cox proportional hazard models were used to identify predictors of time to revision surgery. Predictors of the binary outcome of an immediate complication within 30 days were estimated using logistic regression. <h3>Results</h3> A total of 5,207 patients were included. Mean follow-up was 2,728 days for CDR and 2,542 days for ACDF. Among 4,937 ACDF procedures, 7.5% underwent subsequent revision surgery and among 270 CDR procedures, 8.9% had revision surgery. While the study groups did not differ in their risk of revision surgery (adjusted HR 1.20, 95% CI 0.78-1.85), CDR was associated with a lower probability of an acute complication (adjusted OR 0.41, 95% CI 0.21-0.80). Among other factors, multi-level surgery was an independent predictor of acute complication [OR= 1.33 (95% CI 1.06 – 1.66)]. CDR patients experienced shorter mean (±SD) length of hospital stay [1.42 (±0.87) vs. 2.00 ± (3.08) d for ACDF]. <h3>Conclusions</h3> This study does not demonstrate superiority of CDR over ACDF in revision surgery at the index and/or adjacent level of the cervical spine for single and multi-level procedures. CDR may have an advantage over ACDF in the acute postoperative phase, with a shorter length of hospital stay and lower probability of acute complication. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

215. Assessing key functional outcomes after multilevel fusion for adult spinal deformity in patients over 60 years of age: A prospective, observational, multicenter study with two-year follow-up

<h3>BACKGROUND CONTEXT</h3> Functional disability is a common presentation of adult spinal deformity (ASD). While several studies indicate that operative treatment can provide significant improvement in disability at 2-year follow-up, little information outlines and quantifies which key functions are most affected and improved from surgery. <h3>PURPOSE</h3> To evaluated the short- and long-term changes in self-reported functional outcomes in patients, over age of 60 years, with primary ASD treated with multilevel spinal fusion. <h3>STUDY DESIGN/SETTING</h3> Prospective multicenter cohort study. <h3>PATIENT SAMPLE</h3> This study included 219 patients 60 years or older, from 12 international sites, diagnosed with adult spinal deformity who required at least a 5-level spinal fusion procedure. Surgical procedure was per standard of care at the investigational sites. <h3>OUTCOME MEASURES</h3> Scoliosis Research Society 22r (SRS22r) function domain, and personal care, walking, sitting and standing sections from the Oswestry Disability Index (ODI). <h3>METHODS</h3> Follow-up visits were performed at 10 weeks (± 6 weeks), 12 months (± 2 months) and 24 months (± 2 months). Function was assessed using the Scoliosis Research Society 22r (SRS22r) function domain, and with the personal care, walking, sitting and standing sections from the Oswestry Disability Index (ODI). <h3>RESULTS</h3> A total of 219 patients (mean age 67.5 years old, 80.4% female) out of 255 enrolled met the inclusion criteria. Of those, 179 (82%) patients completed the 2-year study period. SRS22r function domain mean (SD) score was 2.7 (0.7) at baseline and at 10 weeks, and improved (P<0.001) at 12 months (3.4[0.7]) and at 24 months (3.5[0.8]). From baseline to 24 months, ODI questions of walking (2.4 to 1.4), standing (3.1 to 1.7) and social life (2.6 to 1.3) showed the greatest improvements in an unadjusted mixed effect model. In terms of walking, preoperatively vs 2-year postop, 26% vs 63% of patients could walk a mile or more while 53% vs 22% could walk 100 yards or less. Similarly, percentage of patients who could stand >10 minutes improved from 51% to 86%, sitting half an hour or more improved from 74% to 95%, and social life was not restricted in 36% of patients preoperatively compared to 74% at 2 years. Based on the SRS22r question 9, the percentage of patients functioning at 75% or more of their normal work activity improved from 17% preop to 51% at 2 years. <h3>CONCLUSIONS</h3> This study demonstrates and quantifies improvements in specific functions based on patient reported outcome scores in patients greater than 60 years of age undergoing multilevel spinal fusions for ASD. Specifically, significant improvements in standing, walking and social life were recorded at 2-year follow-up. At 24 months, 63% of patients can expect to walk a mile or more, 69% could stand and 95% could sit half an hour or more, and 51% of patients felt they functioned at 75% or better of their normal work. This study provides important practical numbers in terms of expected functional outcome in older patients undergoing multilevel spinal deformity surgery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P133. Is preoperative resolution of leg pain at rest a predictor for successful indirect decompression in anterior and lateral lumbar interbody fusion?

<h3>BACKGROUND CONTEXT</h3> The principle of indirect decompression via lateral and anterior interbody fusion has been investigated previously. Many patients respond well after such an approach, with good improvement in their pain and function. However, there is a group of patients in whom direct decompression may still be necessary. It remains unclear which patients will respond most favorably to indirect decompression. <h3>PURPOSE</h3> This study aims to investigate our hypothesis that preoperative improvement of leg pain at rest is predictive of pain relief via indirect decompression after anterior lumbar (ALIF) or lateral lumbar interbody fusion (LLIF). <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected data at a single institution between 2017 and 2018. <h3>PATIENT SAMPLE</h3> During the study period, 453 patients underwent ALIF or LLIF. Patients who lacked preoperative leg pain, those who underwent multilevel surgery, direct decompression and/or those who lacked three-month postop patient reported outcome measures were excluded. 43 patients met the inclusion criteria. <h3>OUTCOME MEASURES</h3> Patient-reported leg and back pain intensity via the numeric rating scale (NRS) and low back pain related disability scores via the Oswestry Disability Index (ODI) were analyzed. <h3>METHODS</h3> A linear regression model was used to determine whether improvement in leg pain at rest predicted improvements in pain using the NRS and low back pain-related ODI scores at 3 months and 1 year, adjusting for each individual's baseline values. <h3>RESULTS</h3> Forty-three patients (22M, 21F) with a mean age of 66±13 years underwent LLIF (n=34) or ALIF (n=9) with concomitant pedicle screw fixation. Mean NRS scores for preop leg and back pain were 6.2±2.5 and 6.8±2.2, respectively. Mean preop ODI was 44.6±17.6. Mean 3-month NRS leg and back pain scores were 2.0+2.4 and 3.8+2.3 respectively. Mean ODI at 3 months was 28.2+20.6. Preop leg pain improvement at rest was a significant predictor for postop reduction in pain at the 3-month time point when using indirect decompression (p=0.023). When adjusting for preop pain levels, individuals with preop leg pain improvement at rest demonstrated a 2.3±1.0 point greater improvement in NRS leg pain compared to those without preop leg pain improvement at rest (4.3±3.6 vs 1.8±2.3). Results did not differ when correcting for surgery type. Preop leg pain improvement at rest did not predict 1-year pain levels, or changes in disability at either timepoint (p>0.352). <h3>CONCLUSIONS</h3> In this study, improvement in leg pain at rest before surgery was a significant predictor of those patients who were successfully managed via indirect decompression with ALIF or LLIF. Preoperative improvement in leg pain at rest may be used as an important predictive tool for short-term success using indirect decompression. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment.

This systematic review provides supporting evidence for the accompanying clinical practice guideline on the referral of adults with obstructive sleep apnea (OSA) for surgical consultation. The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of upper airway sleep apnea surgery or bariatric surgery to no treatment as well as studies that reported on patient-important and physiologic outcomes pre- and postoperatively. Statistical analyses were performed to determine the clinical significance of using surgery to treat obstructive sleep apnea in adults. Finally, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process was used to assess the evidence for making recommendations. The literature search resulted in 274 studies that provided data suitable for statistical analyses. The analyses demonstrated that surgery as a rescue therapy results in a clinically significant reduction in excessive sleepiness, snoring, blood pressure (BP), apnea-hypopnea index (AHI), respiratory disturbance index (RDI), and oxygen desaturation index (ODI); an increase in lowest oxygen saturation (LSAT) and sleep quality; and an improvement in quality of life in adults with OSA who are intolerant or unaccepting of positive airway pressure (PAP) therapy. The analyses demonstrated that surgery as an adjunctive therapy results in a clinically significant reduction in optimal PAP pressure and improvement in PAP adherence in adults with OSA who are intolerant or unaccepting of PAP due to side effects associated with high pressure requirements. The analyses also demonstrated that surgery as an initial treatment results in a clinically significant reduction in AHI/RDI, sleepiness, snoring, BP, and ODI and an increase in LSAT in adults with OSA and major anatomical obstruction. Analysis of bariatric surgery data showed a clinically significant reduction in BP, AHI/RDI, sleepiness, snoring, optimal PAP level, BMI, and ODI and an increase in LSAT in adults with OSA and obesity. Analyses of very limited evidence suggested that upper airway surgery does not result in a clinically significant increase in risk of serious persistent adverse events and suggested that bariatric surgery may result in a clinically significant risk of iron malabsorption that may be managed with iron supplements. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations. Kent D, Stanley J, Aurora RN, etal. Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment. J Clin Sleep Med. 2021;17(12):2507-2531.

A Dynamic Interbody Cage Improves Bone Formation in Anterior Cervical Surgery: A Porcine Biomechanical Study.

Anterior cervical discectomy and fusion (ACDF) with a rigid interbody spacer is commonly used in the treatment of cervical degenerative disc disease. Although ACDF relieves clinical symptoms, it is associated with several complications such as pseudoarthrosis and adjacent segment degeneration. The concept of dynamic fusion has been proposed to enhance fusion and reduce implant subsidence rate and post-fusion stiffness; this pilot preclinical animal study was conducted to begin to compare rigid and dynamic fusion in ACDF. Using a pig model, we asked, is there (1) decreased subsidence, (2) reduced axial stiffness in compression, and (3) improved likelihood of bone growth with a dynamic interbody cage compared with a rigid interbody cage in ACDF? ACDF was performed at two levels, C3/4 and C5/6, in 10 pigs weighing 48 to 55 kg at the age of 14 to 18 months (the pigs were skeletally mature). One level was implanted with a conventional rigid interbody cage, and the other level was implanted with a dynamic interbody cage. The conventional rigid interbody cage was implanted in the upper level in the first five pigs and in the lower level in the next five pigs. Both types of interbody cages were implanted with artificial hydroxyapatite and tricalcium phosphate bone grafts. To assess subsidence, we took radiographs at 0, 7, and 14 weeks postoperatively. Subsidence less than 10% of the disc height was considered as no radiologic abnormality. The animals were euthanized at 14 weeks, and each operated-on motion segment was harvested. Five specimens from each group were biomechanically tested under axial compression loading to determine stiffness. The other five specimens from each group were used for microCT evaluation of bone ingrowth and ongrowth and histologic investigation of bone formation. Sample size was determined based on 80% power and an α of 0.05 to detect a between-group difference of successful bone formation of 15%. With the numbers available, there was no difference in subsidence between the two groups. Seven of 10 operated-on levels with rigid cages had subsidence on a follow-up radiograph at 14 weeks, and subsidence occurred in two of 10 operated-on levels with dynamic cages (Fisher exact test; p = 0.07). The stiffness of the unimplanted rigid interbody cages was higher than the unimplanted dynamic interbody cages. After harvesting, the median (range) stiffness of the motion segments fused with dynamic interbody cages (531 N/mm [372 to 802]) was less than that of motion segments fused with rigid interbody cages (1042 N/mm [905 to 1249]; p = 0.002). Via microCT, we observed bone trabecular formation in both groups. The median (range) proportions of specimens showing bone ongrowth (88% [85% to 92%]) and bone volume fraction (87% [72% to 100%]) were higher in the dynamic interbody cage group than bone ongrowth (79% [71% to 81%]; p < 0.001) and bone volume fraction (66% [51% to 78%]; p < 0.001) in the rigid interbody cage group. The percentage of the cage with bone ingrowth was higher in the dynamic interbody cage group (74% [64% to 90%]) than in the rigid interbody cage group (56% [32% to 63%]; p < 0.001), and the residual bone graft percentage was lower (6% [5% to 8%] versus 13% [10% to 20%]; p < 0.001). In the dynamic interbody cage group, more bone formation was qualitatively observed inside the cages than in the rigid interbody cage group, with a smaller area of fibrotic tissue under histologic investigation. The dynamic interbody cage provided satisfactory stabilization and percentage of bone ongrowth in this in vivo model of ACDF in pigs, with lower stiffness after bone ongrowth and no difference in subsidence. The dynamic interbody cage appears to be worthy of further investigation. An animal study with larger numbers, with longer observation time, with multilevel surgery, and perhaps in the lumbar spine should be considered.