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Complexities of spine surgery in obese patient populations: a narrative review

Published:December 23, 2019DOI:https://doi.org/10.1016/j.spinee.2019.12.011

      Abstract

      The obese population is particularly challenging to the spine surgeon in all phases of care. A narrative literature review was performed to review difficulties in spine surgery on the obese patient population and techniques for mitigation. We specifically aimed to assess several topics with regard to this population: patient selection and preoperative care; intraoperative and surgical techniques; and postoperative care, outcomes, and complications. The literature review demonstrated that obese patients are at increased surgical risk with spine surgery due to a variety of factors at all stages of intervention. Preoperatively, obese patients have worse outcomes with physical therapy and present technical difficulties for injections. Transport to a hospital, imaging, resuscitation, and intubation are all challenged by increased body habitus. Intraoperatively, obese patients have increased operative times, blood loss, surgical site infections, and nerve palsies. Patient positioning and intraoperative imaging may be limited. Surgery itself may be technically challenging due to body habitus and minimally invasive techniques are becoming more prevalent in this population. Postoperatively, several studies demonstrate that obese patients have inferior outcomes compared with nonobese counterparts. Patient selection is a key for elective interventions, and appropriate infrastructure aids in the ultimate outcomes for both elective and nonelective surgical treatments. Overall, obese patients present several challenges to the spine surgeon, and certain precautions can be undertaken preoperatively, intraoperatively, and postoperatively to mitigate the associated risks to optimize outcomes.

      Keywords

      Introduction

      Obese patients present challenges in all phases of spine-related care and spinal surgery – preoperatively, intraoperatively, and postoperatively. With an increasing prevalence of obesity and an association between obesity and back pain, surgeons will see increasing numbers of obese patients with spine pathologies [
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      Low back pain and lifestyle. Part II–obesity. Information from a population-based sample of 29,424 twin subjects.
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      ]. As Jakoi et al. demonstrate, the prevalence of patients with both lumbar degenerative disk disease and obesity has increased more than 5 times relative to the prevalence of patients with degenerative disk disease without obesity [
      • Jakoi AM
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      ]. Obese patients undergoing surgery, however, are at increased risk of perioperative complications, morbidity, and mortality [
      • Epstein NE
      More risks and complications for elective spine surgery in morbidly obese patients.
      ,
      • Marquez-Lara A
      • Nandyala SV
      • Sankaranarayanan S
      • Noureldin M
      • Singh K
      Body mass index as a predictor of complications and mortality after lumbar spine surgery.
      ,
      • Patel N
      • Bagan B
      • Vadera S
      • Maltenfort MG
      • Deutsch H
      • Vaccaro AR
      • et al.
      Obesity and spine surgery: relation to perioperative complications.
      ,
      • Lingutla KK
      • Pollock R
      • Benomran E
      • Purushothaman B
      • Kasis A
      • Bhatia CK
      • et al.
      Outcome of lumbar spinal fusion surgery in obese patients: a systematic review and meta-Analysis.
      ,
      • Bono OJ
      • Poorman GW
      • Foster N
      • Jalai CM
      • Horn SR
      • Oren J
      • et al.
      Body mass index predicts risk of complications in lumbar spine surgery based on surgical invasiveness.
      ,
      • Castle-Kirszbaum MD
      • Tee JW
      • Chan P
      • Hunn MK
      Obesity in neurosurgery: a narrative review of the literature.
      ,
      • Flippin M
      • Harris J
      • Paxton EW
      • Prentice HA
      • Fithian DC
      • Ward SR
      • et al.
      Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine.
      ,
      • Puvanesarajah V
      • Werner BC
      • Cancienne JM
      • Jain A
      • Pehlivan H
      • Shimer AL
      • et al.
      Morbid obesity and lumbar fusion in patients older than 65 years.
      ,
      • Buerba RA
      • Fu MC
      • Gruskay JA
      • Long WD
      • Grauer JN
      Obese Class III patients at significantly greater risk of multiple complications after lumbar surgery: an analysis of 10,387 patients in the ACS NSQIP database.
      ,
      • Higgins DM
      • Mallory GW
      • Planchard RF
      • Puffer RC
      • Ali M
      • Gates MJ
      • et al.
      Understanding the impact of obesity on short-term outcomes and in-hospital costs after instrumented spinal fusion.
      ,
      • Burks CA
      • Werner BC
      • Yang S
      • Shimer AL
      Obesity is associated with an increased rate of incidental durotomy in lumbar spine surgery.
      ,
      • Phan K
      • Lee NJ
      • Kothari P
      • Kim JS
      • Cho SK
      Risk factors for readmissions following anterior lumbar interbody fusion.
      ,
      • Phan K
      • Kothari P
      • Lee NJ
      • Virk S
      • Kim JS
      • Cho SK
      Impact of obesity on outcomes in adults undergoing elective posterior cervical fusion.
      ,
      • McGuire KJ
      • Khaleel MA
      • Rihn JA
      • Zhao W
      • Weinstein JN
      • Israel B
      • et al.
      The effect of high obesity on outcomes of treatment for Lumbar Spinal Conditions.
      ,
      • Olsen MA
      • Mayfield J
      • Lauryssen C
      • Polish LB
      • Jones M
      • Vest J
      • et al.
      Risk factors for surgical site infection in spinal surgery.
      ]. Increased body mass index (BMI) has been demonstrated to affect outcomes in all age groups. Studies have shown that obese adolescents undergoing spinal fusion for adolescent idiopathic scoliosis and obese adults undergoing spinal deformity surgery do worse than their nonobese counterparts [
      • De la Garza Ramos R
      • Nakhla J
      • Nasser R
      • Schulz JF
      • Purvis TE
      • Sciubba DM
      • et al.
      Effect of body mass index on surgical outcomes after posterior spinal fusion for adolescent idiopathic scoliosis.
      ,
      • Amin RM
      • Raad M
      • Jain A
      • Sandhu KP
      • Frank SM
      • Kebaish KM
      Increasing body mass index is associated with worse perioperative outcomes and higher costs in adult spinal deformity surgery.
      ].
      Obesity is a growing epidemic that is starting to gain more attention in the spine literature. An increasing number of studies are being published that document the significantly increased risk of operating on the obese patient [
      • Epstein NE
      More risks and complications for elective spine surgery in morbidly obese patients.
      ,
      • Marquez-Lara A
      • Nandyala SV
      • Sankaranarayanan S
      • Noureldin M
      • Singh K
      Body mass index as a predictor of complications and mortality after lumbar spine surgery.
      ,
      • Patel N
      • Bagan B
      • Vadera S
      • Maltenfort MG
      • Deutsch H
      • Vaccaro AR
      • et al.
      Obesity and spine surgery: relation to perioperative complications.
      ,
      • Lingutla KK
      • Pollock R
      • Benomran E
      • Purushothaman B
      • Kasis A
      • Bhatia CK
      • et al.
      Outcome of lumbar spinal fusion surgery in obese patients: a systematic review and meta-Analysis.
      ,
      • Bono OJ
      • Poorman GW
      • Foster N
      • Jalai CM
      • Horn SR
      • Oren J
      • et al.
      Body mass index predicts risk of complications in lumbar spine surgery based on surgical invasiveness.
      ,
      • Castle-Kirszbaum MD
      • Tee JW
      • Chan P
      • Hunn MK
      Obesity in neurosurgery: a narrative review of the literature.
      ,
      • Flippin M
      • Harris J
      • Paxton EW
      • Prentice HA
      • Fithian DC
      • Ward SR
      • et al.
      Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine.
      ,
      • Puvanesarajah V
      • Werner BC
      • Cancienne JM
      • Jain A
      • Pehlivan H
      • Shimer AL
      • et al.
      Morbid obesity and lumbar fusion in patients older than 65 years.
      ,
      • Buerba RA
      • Fu MC
      • Gruskay JA
      • Long WD
      • Grauer JN
      Obese Class III patients at significantly greater risk of multiple complications after lumbar surgery: an analysis of 10,387 patients in the ACS NSQIP database.
      ,
      • Higgins DM
      • Mallory GW
      • Planchard RF
      • Puffer RC
      • Ali M
      • Gates MJ
      • et al.
      Understanding the impact of obesity on short-term outcomes and in-hospital costs after instrumented spinal fusion.
      ,
      • Burks CA
      • Werner BC
      • Yang S
      • Shimer AL
      Obesity is associated with an increased rate of incidental durotomy in lumbar spine surgery.
      ,
      • Phan K
      • Lee NJ
      • Kothari P
      • Kim JS
      • Cho SK
      Risk factors for readmissions following anterior lumbar interbody fusion.
      ,
      • Phan K
      • Kothari P
      • Lee NJ
      • Virk S
      • Kim JS
      • Cho SK
      Impact of obesity on outcomes in adults undergoing elective posterior cervical fusion.
      ,
      • McGuire KJ
      • Khaleel MA
      • Rihn JA
      • Zhao W
      • Weinstein JN
      • Israel B
      • et al.
      The effect of high obesity on outcomes of treatment for Lumbar Spinal Conditions.
      ,
      • Olsen MA
      • Mayfield J
      • Lauryssen C
      • Polish LB
      • Jones M
      • Vest J
      • et al.
      Risk factors for surgical site infection in spinal surgery.
      ]. Puvanesarajah et al., for example, demonstrated that obese and morbidly obese patients older than 65 years undergoing lumbar fusion had significantly higher odds of experiencing a major medical complication, wound infection, wound dehiscence, and 30-day readmission, as well as incurring longer length of stay and in-hospital costs [
      • Puvanesarajah V
      • Werner BC
      • Cancienne JM
      • Jain A
      • Pehlivan H
      • Shimer AL
      • et al.
      Morbid obesity and lumbar fusion in patients older than 65 years.
      ]. Phan et al. likewise determined that morbidly obese patients undergoing posterior cervical fusion had increased risk of venous thromboembolism, and those undergoing anterior lumbar interbody fusion had increased risk for 30-day readmissions [
      • Phan K
      • Lee NJ
      • Kothari P
      • Kim JS
      • Cho SK
      Risk factors for readmissions following anterior lumbar interbody fusion.
      ,
      • Phan K
      • Kothari P
      • Lee NJ
      • Virk S
      • Kim JS
      • Cho SK
      Impact of obesity on outcomes in adults undergoing elective posterior cervical fusion.
      ]. Burks et al. demonstrated that obesity is associated with increased rates of incidental durotomy in lumbar spine surgery [
      • Burks CA
      • Werner BC
      • Yang S
      • Shimer AL
      Obesity is associated with an increased rate of incidental durotomy in lumbar spine surgery.
      ]. The spine surgeon, thus, can encounter complications preoperatively before an incision is made, intraoperatively, and/or postoperatively. This paper reviews the challenges of managing spine pathology in obese patients, and provides some tips to try to mitigate the risks.

      Literature review

      Preoperative, intraoperative, and postoperative issues with obese patients undergoing spine surgery were explored. Pubmed and Google scholar searches were performed using keywords “obesity,” “obese,” “spine,” and “surgery.” Article abstracts were assessed for relevancy. Secondary review of bibliographies of applicable articles was reviewed for additional relevant articles. Tertiary searches were done to answer additional questions in relation to perioperative care in this patient population.

      Preoperative challenges

      Elective surgery

      Obesity is a modifiable risk factor that has been shown to be associated with several spinal disorders across various age and sex groups [
      • Green BN
      • Johnson CD
      • Haldeman S
      • Griffith E
      • Clay MB
      • Kane EJ
      • et al.
      A scoping review of biopsychosocial risk factors and co-morbidities for common spinal disorders.
      ]. Conservative treatment for elective cases may include physical therapy, injections, nonsteroidal anti-inflammatory drugs, and muscle relaxants. Analysis of the Spine Patient Outcomes Research Trial demonstrated that obese (BMI ≥30) patients with lumbar stenosis undergoing nonoperative treatment did worse with regards to Oswestry Disability Index and the bodily pain and physical function domains of the SF-36 when compared with patients with BMI <30 [

      Rihn JA, Radcliff K, Hilibrand AS, Anderson DT, Zhao W, Lurie J, et al. Does obesity affect outcomes of treatment forfor lumbar stenosis. Spine (Phila Pa 1976) Author Manuscript. Author manuscript; available in PMC 2013 November 01. 2012 November 1; 2012; 37(23): 1933–46. https://doi.org/10.1097/BRS.0b013e31825e21b2. and degenerative spond 2013;37:1933–46.https://doi.org/10.1097/BRS.0b013e31825e21b2.Does.

      ]. Similarly, obese patients with degenerative spondylolisthesis had similar SF-36 bodily pain scores but less improvement in the SF-36 physical function and Oswestry Disability Index scores compared with their nonobese counterparts [

      Rihn JA, Radcliff K, Hilibrand AS, Anderson DT, Zhao W, Lurie J, et al. Does obesity affect outcomes of treatment forfor lumbar stenosis. Spine (Phila Pa 1976) Author Manuscript. Author manuscript; available in PMC 2013 November 01. 2012 November 1; 2012; 37(23): 1933–46. https://doi.org/10.1097/BRS.0b013e31825e21b2. and degenerative spond 2013;37:1933–46.https://doi.org/10.1097/BRS.0b013e31825e21b2.Does.

      ]. With regards to physical therapy, obesity has been shown to be an independent predictor of treatment failure [
      • Eleswarapu AS
      • Divi SN
      • Dirschl DR
      • Mok JM
      • Stout C
      • Lee MJ
      How effective is physical therapy for common low back pain diagnoses?.
      ]. Transforaminal epidural steroid injections are another effective conservative treatment option for lumbar disk herniation and radicular pain relief [
      • Manchikanti L
      • Buenaventura RM
      • Manchikanti KN
      • Ruan X
      • Gupta S
      • Smith HS
      • et al.
      Effectiveness of therapeutic lumbar transforaminal epidural steroid injections in managing lumbar spinal pain.
      ]. However, the obese patient population presents challenges with regards to fluoroscopy due to potentially difficult visualization of landmarks and need for longer needles. Cushman et al. demonstrated that obese patients had significantly longer mean fluoroscopy times and radiation doses during lumbar transforaminal epidural steroid injections [
      • Cushman D
      • Mattie R
      • Curtis B
      • Flis A
      • McCormick ZL
      The effect of body mass index on fluoroscopic time and radiation dose during lumbar transforaminal epidural steroid injections.
      ].
      Weight reduction in itself can have an effect on back pain, as Khoueir et al. demonstrated that substantial weight loss after bariatric surgery may be associated with moderate reductions in pre-existing back pain at early-follow-up [
      • Khoueir P
      • Black MH
      • Crookes PF
      • Kaufman HS
      • Katkhouda N
      • Wang MY
      Prospective assessment of axial back pain symptoms before and after bariatric weight reduction surgery.
      ]. Similarly, Lidar et al. demonstrated bariatric surgery and weight reduction is associated with a significant decrease in low back pain, radicular pain, and marked increase in L4–L5 intervertebral disk height [
      • Lidar Z
      • Behrbalk E
      • Regev GJ
      • Salame K
      • Keynan O
      • Schweiger C
      • et al.
      Intervertebral disc height changes after weight reduction in morbidly obese patients and its effect on quality of life and radicular and low back pain.
      ]. Preoperative weight loss may prevent a percentage of patients from requiring spine procedures, and perhaps bariatric surgery, in the setting of elective spine surgery, should be utilized to optimize outcomes. One case report, for example, illustrated a super obese patient who had improvement in his myelopathy following bariatric surgery, suspected secondary to a change in spinal alignment [
      • Takenaka S
      • Mukai Y
      • Hosono N
      • Kaito T
      Improvement of thoracic myelopathy following bariatric surgery in an obese patient.
      ]. Jain et al., additionally, demonstrated that patients undergoing bariatric surgery before elective posterior lumbar fusion had lower rates of respiratory failure, urinary tract infection, acute renal failure, infection, overall medical complications, and lower hospital length of stay compared with obese patients with BMI over 40 [
      • Jain D
      • Berven SH
      • Carter J
      • Zhang AL
      • Deviren V
      Bariatric surgery before elective posterior lumbar fusion is associated with reduced medical complications and infection.
      ].
      Bariatric surgery and its relation to spine outcomes is not without controversy, however, as some studies have demonstrated bariatric surgery results in a greater risk of osteoporosis, reduced bone mineral density, Vitamin D deficiency, and an increased risk of spinal fractures [
      • Epstein NE
      More risks and complications for elective spine surgery in morbidly obese patients.
      ]. Shanbhogue et al. determined that bone loss and deterioration of bone strength in the hip and spine continue into the years after gastric bypass, despite weight stabilization and maintenance of metabolic parameters [
      • Shanbhogue VV
      • Støving RK
      • Frederiksen KH
      • Hanson S
      • Brixen K
      • Gram J
      • et al.
      Bone structural changes after gastric bypass surgery evaluated by HR-pQCT: a two-year longitudinal study.
      ]. The potential risk of reduced bone mineral density must be weighed against the potential benefit of reduced axial back pain [
      • Epstein N
      Bariatric bypasses contribute to loss of bone mineral density but reduce axial back pain in morbidly obese patients considering spine surgery.
      ]. Perhaps targeted preoperative evaluations, such as the subcutaneous lumbar spine index, can help stratify the risk of surgery in an obese patient to determine which course of action a surgeon should take, particularly in those with viable nonoperative options [
      • Shaw K
      • Chen J
      • Sheppard W
      • Alazzeh M
      • Park H
      • Park D
      • et al.
      Use of the subcutaneous lumbar spine (SLS) index as a predictor for surgical complications in lumbar spine surgery.
      ].

      Nonelective surgery

      As Rosenfeld et al. describe, several logistical challenges exist for morbidly obese patients even before arrival to a hospital [
      • Rosenfeld HE
      • Limb R
      • Chan P
      • Fitzgerald M
      • Bradley WPL
      • Rosenfeld JV
      Challenges in the surgical management of spine trauma in the morbidly obese patient: a case series.
      ]. Patients sustaining trauma or being found down are often delayed in transport and transfer to an appropriate trauma level of care institution as often times special transport equipment is not readily available. It is not uncommon for emergency medical services to inquire about patient weight and size before arriving on the scene for better planning [
      • Lombardi R
      • Stephenson J
      Bariatric patients and aeromedical retrieval.
      ]. Traditional stretchers have average size limitations of 270–318 kg but modifications have been developed for the larger patient. Specially designed ambulances may need to be utilized. Additionally, rotary or small fixed-wing aircraft have weight and size constraints which may limit transfer to that by road only. Smaller EMS helicopters for example, carry patients with a maximum of 135 kg whereas fixed-wing aircraft have limits of 260 kg [
      • Lombardi R
      • Stephenson J
      Bariatric patients and aeromedical retrieval.
      ]. Additional challenges include obtaining intravenous access (may require intraosseous access), measuring appropriate blood pressure due to inadequately sized cuffs, or applying appropriate cervical spine immobilization due to an ill-fitting collar. In that case, taped towel rolls may be applied to each side of the head for stabilization.
      Upon arrival to an institution, obese individuals face several imaging limitations [
      • Le NTT
      • Robinson J
      • Lewis SJ
      Obese patients and radiography literature: what do we know about a big issue?.
      ,
      • Spitler CA
      • Hulick RM
      • Graves ML
      • Russell GV
      • Bergin PF
      Obesity in the polytrauma patient.
      ]. Magnetic resonance imaging [MRI] may be not possible in this patient population, which is generally dependent upon the patient's weight (due to table weight limits) as well as maximum girth (due to limitations of closed MRI dimensions). Furthermore, computed tomography (CT) scans may be of limited utility in these groups. Bony anatomy in CT scan may be difficult to visualize due to excess soft tissue or averaging artifact and even CT myelogram may be of limited utility in this population (Fig. 1). Limited or nonexistent preoperative imaging may lead to incorrect diagnoses, poor surgical planning, and overall increased surgical risk. Discussion with patient and family regarding these limitations and their effect on surgical planning is necessary. Alternatives to surgery are similarly limited. If the bariatric spine patient is to be treated with an orthotic, it may be difficult to obtain one that is appropriately sized. Due to excess soft adipose tissue, obese patients have additional protection of visceral organs; the energy, however, is transmitted to the axial and appendicular osseous structures and obese patients are more likely to sustain pelvic or extremity fractures [
      • Spitler CA
      • Hulick RM
      • Graves ML
      • Russell GV
      • Bergin PF
      Obesity in the polytrauma patient.
      ].
      Fig 1
      Fig. 1Super obese patients present limitations in pre- and postoperative imaging as well as patient positioning. (Left) Myelogram demonstrates poor penetration due to body habitus. MRI was not possible due to excessive body girth. (Middle) Tape was used to manage skin folds. (Right) Postoperative films after a C3-C7 laminectomy and fusion based upon the presumption of levels of stenosis due to limited imaging (seen in Left) in the classic clinical setting of myelopathy.

      Anesthetic issues

      If surgery is indicated, obese patients present particular challenges in relation to anesthesia [
      • Baxi V
      • Budhakar S
      Anesthesia management of a morbidly obese patient in prone position for lumbar spine surgery.
      ,
      • Douglass J
      • Fraser J
      • Andrzejowski J
      Awake intubation and awake prone positioning of a morbidly obese patient for lumbar spine surgery.
      ]. Obesity is associated with cardiac and pulmonary hypertension, ventricular deficiency, heart disease, and obstructive sleep apnea among other comorbidities, and particular attention needs to be paid in the preoperative evaluation. Obese trauma patients generally have higher base deficits than nonobese counterparts and are often under-resuscitated due to fluid and blood products not adjusted for their size [
      • Spitler CA
      • Hulick RM
      • Graves ML
      • Russell GV
      • Bergin PF
      Obesity in the polytrauma patient.
      ]. At times preoperative optimization is needed with BiPAP ventilation or respiratory physiotherapy. Intubation is more difficult due to increased neck circumference and poor visibility of the oropharynx, and may require fiberoptic assistance. Prone positioning adds additional risk of airway loss, and itself is challenging in the obese population. Douglass et al. describe awake fiberoptic intubation and awake prone positioning to overcome difficulties in transferring an anesthetized bariatric patient into the prone position [
      • Douglass J
      • Fraser J
      • Andrzejowski J
      Awake intubation and awake prone positioning of a morbidly obese patient for lumbar spine surgery.
      ]. Additional limitations in the morbidly obese include more difficult mechanical ventilation due to a restrictive chest wall, less accurate monitoring, easier dislodgement of endotracheal tubes, and increased susceptibility to airway edema and obstruction [
      • Rosenfeld HE
      • Limb R
      • Chan P
      • Fitzgerald M
      • Bradley WPL
      • Rosenfeld JV
      Challenges in the surgical management of spine trauma in the morbidly obese patient: a case series.
      ]. Lateral position may improve cardiovascular issues as the pannus is displaced away from the diaphragm and inferior vena cava [
      • Spitler CA
      • Hulick RM
      • Graves ML
      • Russell GV
      • Bergin PF
      Obesity in the polytrauma patient.
      ]. Postoperatively, residual accumulation of anesthetics in the adipose tissue may affect ease of extubation, and a planned extubation may be required in the intensive care unit.

      Operative challenges

      Cao et al. performed a meta-analysis demonstrating that obesity is associated with longer operative times, greater postoperative blood loss, higher risk of surgical site infections, and higher risk of nerve injuries in lumbar spine surgery [
      • Cao J
      • Kong L
      • Meng F
      • Zhang Y
      • Shen Y
      Impact of obesity on lumbar spinal surgery outcomes.
      ]. Lingutla et al. similarly performed a systematic review and meta-analysis of lumbar spine fusion in obese and nonobese patients and found greater intraoperative blood loss, longer duration of surgeries, and more complications in the obese patients [
      • Lingutla KK
      • Pollock R
      • Benomran E
      • Purushothaman B
      • Kasis A
      • Bhatia CK
      • et al.
      Outcome of lumbar spinal fusion surgery in obese patients: a systematic review and meta-Analysis.
      ].
      Several studies illustrate that increased BMI is associated with increased blood loss or transfusion risk. Onyekwelu et al. demonstrated higher blood product requirement and extended hospital stay in obese patients requiring lumbar fusion [
      • Onyekwelu I
      • Glassman SD
      • Asher AL
      • Shaffrey CI
      • Mummaneni PV
      • Carreon LY
      Impact of obesity on complications and outcomes: a comparison of fusion and nonfusion lumbar spine surgery.
      ]. Shamji et al. found that higher BMI to be associated with increased transfusion requirements and likelihood of discharge to assisted living after thoracolumbar spine fusion [
      • Shamji MF
      • Parker S
      • Cook C
      • Pietrobon R
      • Brown C
      • Isaacs RE
      Impact of body habitus on perioperative morbidity associated with fusion of the thoracolumbar and lumbar spine.
      ]. Longer operating time may be the etiology of greater intraoperative blood loss, or due to increased venous bleeding due to increased intra-abdominal or intrathoracic pressures. The surgeon should be prepared and have additional blood ready for high-risk patients or can consider use of the Cell Saver (Haemonetics Corp). Meta-analyses and systematic reviews have also demonstrated that tranexamic acid reduces perioperative blood loss and blood transfusions, and should be utilized in appropriate cases [
      • Zhang Y
      • Liu H
      • He F
      • Chen A
      • Yang H
      • Pi B
      Does tranexamic acid improve bleeding, transfusion, and hemoglobin level in patients undergoing multilevel spine surgery? A systematic review and meta-analysis.
      ,
      • Cheriyan T
      • Maier SP
      • Bianco K
      • Slobodyanyuk K
      • Rattenni RN
      • Lafage V
      • et al.
      Efficacy of tranexamic acid on surgical bleeding in spine surgery: a meta-analysis.
      ]. Neuromonitoring may also be more difficult in obese patients; needles need to be long enough to reach the muscle and higher BMI has been shown to be associated with false positive alerts with transcranial motor-evoked potential monitoring [
      • Kim DH
      • Zaremski J
      • Kwon B
      • Jenis L
      • Woodard E
      • Bode R
      • et al.
      Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy.
      ].
      A majority of studies reveal an association between obesity and surgical site infections. Olsen et al. performed a retrospective study to assess risk factors for surgical site infections in spine surgery and found morbid obesity with BMI >35 to be an independent risk factor [
      • Olsen MA
      • Mayfield J
      • Lauryssen C
      • Polish LB
      • Jones M
      • Vest J
      • et al.
      Risk factors for surgical site infection in spinal surgery.
      ]. Spine surgeons operating on high risk populations can take special measures to limit postoperative wound complications. Multicenter studies, systematic reviews, and meta-analyses have demonstrated that intrawound, prophylactic vancomycin powder decreases the risk of developing surgical site infections, although some studies express concern about its effects on increasing the incidence of gram-negative and polymicrobial surgical site infections or potential for pseudoarthrosis [
      • Khan NR
      • Thompson CJ
      • DeCuypere M
      • Angotti JM
      • Kalobwe E
      • Muhlbauer MS
      • et al.
      A meta-analysis of spinal surgical site infection and vancomycin powder.
      ,
      • Kang DG
      • Holekamp TF
      • Wagner SC
      • Lehman RA
      Intrasite vancomycin powder for the prevention of surgical site infection in spine surgery : a systematic literature review.
      ,
      • Bakhsheshian J
      • Dahdaleh NS
      • Lam SK
      • Savage JW
      • Smith ZA
      The use of vancomycin powder in modern spine surgery : systematic review and meta-analysis of the clinical evidence.
      ,
      • Gande A
      • Rosinski A
      • Cunningham T
      • Bhatia N
      • Lee Y
      Selection pressures of vancomycin powder use in spine surgery: a meta-analysis.
      ,
      • Devin CJ
      • Chotai S
      • McGirt MJ
      • Vaccaro AR
      • Youssef JA
      • Orndorff DG
      • et al.
      Intrawound vancomycin decreases the risk of surgical site infection after posterior spine surgery: a multicenter analysis.
      ]. Copious irrigation with antimicrobial solution (eg, bacitracin or povidone-iodine in saline), multilayer closure to obliterate the dead space, placement of postoperative drains, occlusive dressings, postoperative antibiotics, and nasal/body decontamination have also been described as potential interventions to limit infections, although the evidence is limited [
      • Yamada K
      • Abe H
      • Higashikawa A
      • Tonosu J
      • Kuniya T
      • Nakajima K
      • et al.
      Evidence-based care bundles for preventing surgical site infections in spinal instrumentation surgery.
      ,
      • Andrew Glennie R
      • Dea N
      • Street JT
      Dressings and drains in posterior spine surgery and their effect on wound complications.
      ,
      • Yao R
      • Tan T
      • Tee JW
      • Street J
      Prophylaxis of surgical site infection in adult spine surgery: a systematic review.
      ].
      Obese patients may require unique operative room set-up and positioning [
      • Spitler CA
      • Hulick RM
      • Graves ML
      • Russell GV
      • Bergin PF
      Obesity in the polytrauma patient.
      ]. Multiple people—that is, lift teams—are required for positioning, both for sake of the patient and the health-care providers; in fact, some states have passed legislature pertaining to manual patient lifting [
      • Hudson MA
      Texas passes first law for safe patient handling in America: landmark legislation protects health-care workers and patients from injury related to manual patient lifting.
      ]. Obese individuals may exceed the weight limits of the spine-capable operative tables, which often vary from 500 to 1000 pounds. In these instances, it may be possible to utilize a setup with two flat Jackson beds, belted together, with a Wilson frame strapped straddling both beds if the Wilson frame has a higher weight rating (Fig. 2). Care must be taken, however, to ensure that the weight limit of the Wilson frame is not exceeded. Alternatively, the patient may be placed on large gel rolls (eg, under sternum and pelvis). One challenge in prone positioning is the accommodation of an obese abdomen (or in some cases a large ventral hernia). The inability to position patients with a free-hanging abdomen may lead to increased intra-abdominal pressure and subsequently increased epidural venous pressure and bleeding during surgery. Although some patients can fit on a single Jackson frame, which can accommodate the abdomen, care must be taken to place additional padding around the sides of the frame to prevent skin pressure breakdown. Although these techniques can accommodate the weight of such patients, one limitation includes difficulty safely positioning the head and neck, which are often far above the level of the bed due to abdominal obesity. One option is to suspend the neck in tongs hooked up to 8–10 pounds of traction, which allows neutral positioning of the head and neck without placing the face in a standard padded head holder, decreasing not only the risk for pressure sores to the face, but also decreasing intraocular pressure and potentially the risk of postoperative vision loss [
      • Emery SE
      • Daffner SD
      • France JC
      • Ellison M
      • Grose BW
      • Hobbs GR
      • et al.
      Effect of head position on intraocular pressure during lumbar spine fusion.
      ]. Particular care must be paid to appropriate padding, particularly of the extremities, as morbidly obese patients, especially those with BMI greater than 40, are at an increased risk of positioning-related peripheral neuropathy [
      • Patel N
      • Bagan B
      • Vadera S
      • Maltenfort MG
      • Deutsch H
      • Vaccaro AR
      • et al.
      Obesity and spine surgery: relation to perioperative complications.
      ]. Finally, due to body habitus and positioning modifications, the patient may be relatively unstable on the bed; the use of wide silk tape can help secure the patient in place.
      Fig 2
      Fig. 2Positioning issues when a patient outweighs the table maximum weight. Two Jackson tables may be utilized with the patient centered on a Wilson frame strapped to both. Several straps hold the two beds together and extra material is necessary to support the head which is elevated off the table surface. Extra padding is used to accommodate the pannus and to maintain spinal alignment. Multiple people are required to position. The C-arm is arced overhead as it cannot be positioned around both beds and patient.
      Fluoroscopy is well-known to be more difficult in obese patient populations [
      • Le NTT
      • Robinson J
      • Lewis SJ
      Obese patients and radiography literature: what do we know about a big issue?.
      ]. Compromised intraoperative imaging due to excess soft tissue may lead to difficult visualization (Fig. 3) or, worse, wrong level surgery. Anteroposterior (AP) views may be required to localize the surgical levels to provide a targeted incision if possible. Similarly, AP views may be useful in incision planning to find midline, when the midline is not palpable or otherwise apparent, nor will it reliably be at the apparent center of the field due to drift of the patient on the bed. Intraoperative CT or navigation may be considered in patients where radiography is central to instrumentation, although image quality is generally significantly degraded in more obese individuals and any specialized tables required for the use of navigation may have insufficient weight limits. Additionally, intraoperative O-arm devices or CT scanners may not have a large enough aperture to accommodate some patients. Flipping the C-arm over the operative table may be required as its diameter will not accommodate going around a double-table set up (Fig. 2). Fluoroscopy images may need to be taken in an oblique nature if a true lateral is unable to be obtained due to size limitations. This, however, requires the surgeon to be familiar with the appearance of normal anatomic structures in the infrequently used oblique projection, which may limit image utility. Furthermore, the difficulty of operating across such a wide field should not be underestimated. It may be required to deem the bottom (or sides lateral to the patient) of the operative table as “nonsterile” and either lean or kneel on any available space alongside the patient (keeping in mind this addition also factors into the total weight limit of the two beds). In both anterior and posterior cervical surgery, consideration should be given to a steep incline of the bed in order to both help ventilation and to utilize gravity to pull the excess tissue away from the operative field and improve radiographic images. Wide silk tape may be used to help straighten skin folds and keep the peri-incisional skin relatively taut, although too much traction may lead to skin breakdown.
      Fig 3:
      Fig. 3Poor quality intraoperative images in super obese patients increase the difficulty of spine surgery.
      Significantly obese patients additionally provide technical surgical limitations, with poor operative corridors, poor visualization, and possibly suboptimal instrumentation if the surgical field is limited. Longer incisions may be required. Longer instruments (eg, bayoneted bipolar forceps or Kerrisons) may alleviate some difficulty in working in deep incisions. Weitlaners utilized vertically and stacked may be reasonable retraction when exposure width is limited as compared with depth (ie, cervical spine). The use of self-retaining abdominal retractor frame systems, with their relatively long blades, may be beneficial for posterior spinal exposures in obese patients. Additionally, Phan et al. have demonstrated lower fusion rates in obese (60%) compared with normal-weight (88.2%) and overweight patients (76%) [
      • Phan K
      • Rogers P
      • Rao PJ
      • Mobbs RJ
      Influence of obesity on complications, clinical outcome and subsidence following anterior lumbar interbody fusion (ALIF): prospective observational study.
      ]. Bone autograft harvesting can be technically challenging, so allograft or substitute may need to be used. These patients are clearly in a demographic to benefit from minimally invasive surgery (MIS) techniques; however, it has been our preference to not do such cases percutaneously (and have had to abort such attempts), purely due to the difficulty of securing adequate radiographic anatomical markers without excessive radiation to the surgical team. When considering percutaneous screw placement, one useful technique is creating a midline incision down to fascia and inserting Jamshidi needles through fascial incisions rather than skin incisions, in order to minimize parallax effects, improve maneuverability of the Jamshidis, and in order to accommodate the length of the Jamshidi, which may be insufficient for some obese patients. In this instance, AP views may need to be obtained with saline irrigation in the wound. The anterior retroperitoneal approach is also feasible in the overweight or obese cohort; obese patients have been shown to have increased durations of surgery and longer lengths and depths of incisions, but similar vascular and infectious complications compared with patients of normal weight [
      • Lucas F
      • Emery E
      • Dudoit T
      • Berger L
      Influence of obesity on access-related complications during anterior lumbar spine interbody fusion.
      ,
      • Peng CWB
      • Bendo JA
      • Goldstein JA
      • Nalbandian MM
      Perioperative outcomes of anterior lumbar surgery in obese versus non-obese patients.
      ].
      Recent studies have demonstrated good results with MIS techniques, although obese patients may have increased surgery time, increased complications and less clinical benefits compared with nonobese counterparts [
      • IV JC
      • Jackson T
      Minimally invasive lumbar discectomy in obese patients.
      ,
      • Kapetanakis S
      • Gkantsinikoudis N
      • Chaniotakis C
      • Charitoudis G
      • Givissis P
      Percutaneous transforaminal endoscopic discectomy for the treatment of lumbar disc herniation in obese patients: health-related quality of life assessment in a 2-year follow-up.
      ,
      • Wang T
      • Han C
      • Jiang H
      • Tian P
      The effect of obesity on clinical outcomes after minimally invasive surgery of the spine: a systematic review and meta-analysis.
      ]. Bohl et al., for example, demonstrated that greater BMI is an independent risk factor for undergoing a revision procedure following a single level MIS lumbar discectomy [
      • Bohl DD
      • Ahn J
      • Mayo BC
      • Massel DH
      • Tabaraee E
      • Sershon RA
      • et al.
      Does greater body mass index increase the risk for revision procedures following a single-level minimally invasive lumbar discectomy?.
      ]. MIS techniques, compared with conventional open procedures, however, may provide similar outcomes while decreasing incision length, blood loss, operative time, and length of stay [
      • Tomasino A
      • Parikh K
      • Steinberger J
      • Knopman J
      • Boockvar J
      • Härtl R
      Tubular microsurgery for lumbar discectomies and laminectomies in obese patients: operative results and outcome.
      ]. Adogwa et al. reviewed patients with BMI >30 and demonstrated similar improvement in pain, functional disability, and complication rates when comparing elective open versus MIS-transforaminal lumbar interbody fusion (TLIF) for degenerative disk disease or Grade I spondylolisthesis with central or foraminal stenosis who failed medical management [
      • Adogwa O
      • Carr K
      • Thompson P
      • Hoang K
      • Darlington T
      • Perez E
      • et al.
      A prospective, multi-institutional comparative effectiveness study of lumbar spine surgery in morbidly obese patients: does minimally invasive transforaminal lumbar interbody fusion result in superior outcomes?.
      ]. Similar TLIF results were seen by Lau et al. in which obese patients had equivalent clinical outcomes and complication rates compared patients with normal weight [
      • Lau D
      • Ziewacz J
      • Park P
      Minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis in patients with significant obesity.
      ]. Lastly, Park et al. demonstrated similar complication risks when comparing patients over and under BMI of 25 undergoing MIS spine surgery [

      Park P, Upadhyaya C, Garton HJ FK. The Impact of Minimally Invasive spine surgery on perioperative complications in overweight or obese patients. Neurosurgery 2008;62(3):693–9. Discussion 693–9 2008;62:693–9. https://doi.org/10.1227/01.NEU.0000297115.62323.CE.

      ]. MIS techniques, however, have steep learning curves with potential for difficult access to the spine pathology, greater working distances, and poor imaging quality; therefore, proper surgical training, suitable patient selection, and careful choice of surgical materials is important [
      • Kapetanakis S
      • Gkantsinikoudis N
      • Chaniotakis C
      • Charitoudis G
      • Givissis P
      Percutaneous transforaminal endoscopic discectomy for the treatment of lumbar disc herniation in obese patients: health-related quality of life assessment in a 2-year follow-up.
      ,
      • Bae JS
      • Lee S-H
      Transforaminal full-endoscopic lumbar discectomy in obese patients.
      ].

      Postoperative issues, complications, and outcomes

      Postoperatively, it is important to mobilize bariatric patients as soon as is safe and possible. Additional people and equipment may be necessary to decrease risk of injury to the patient and health-care employees; motorized ceiling lifts and “lift teams” have been shown to decrease the rate of hospital-acquired pressure ulcers, decrease patient handling-related employee injuries, and improve employee satisfaction while decreasing hospital costs [
      • Walden CM
      • Bankard SB
      • Cayer B
      • Floyd WB
      • Garrison HG
      • Hickey T
      • et al.
      Mobilization of the obese patient and prevention of injury.
      ]. A multidisciplinary team, including nutritionists, dieticians, social workers, and physical and occupational therapists should be involved. Obese patients are at an increased risk of venous thromboembolism, which is further compounded in trauma patients [
      • Rosenfeld HE
      • Limb R
      • Chan P
      • Fitzgerald M
      • Bradley WPL
      • Rosenfeld JV
      Challenges in the surgical management of spine trauma in the morbidly obese patient: a case series.
      ]. Sequential compression devices, if able to be fitted appropriately, along with appropriate weight-adjusted dosing of low-molecular-weight heparin (LMWH) prophylaxis help reduce incidence of deep venous thrombosis and pulmonary embolism. For high risk patients, (eg, obese patient with spinal cord injury), prophylactic vena cava filters or initiation of anticoagulation may be warranted and has been done at our institution.
      Several studies suggest that postoperative outcomes are inferior in the obese population compared with the nonobese population. Giannadakis et al. determined that nonobese patients had more improvement in back and leg pain and had shorter surgeries in the setting of decompressive surgery for lumbar spinal stenosis [
      • Giannadakis C
      • Nerland US
      • Solheim O
      • Jakola AS
      • Gulati M
      • Weber C
      • et al.
      Does obesity affect outcomes after decompressive surgery for lumbar spinal stenosis? A multicenter, observational, registry-based study.
      ]. Onyekwelu et al. similarly demonstrated slightly worse back pain scores at 2 years postoperatively in obese patients requiring lumbar decompression without fusion [
      • Onyekwelu I
      • Glassman SD
      • Asher AL
      • Shaffrey CI
      • Mummaneni PV
      • Carreon LY
      Impact of obesity on complications and outcomes: a comparison of fusion and nonfusion lumbar spine surgery.
      ]. Elsayed et al. demonstrated that both obese and nonobese patients had significant improvements in pain scores after lumbar decompressive surgery for stenosis, but obese patients continued to report greater pain at 3 months postoperatively that later resolved by 12 months [
      • Elsayed G
      • Davis MC
      • Dupépé EC
      • McClugage SG
      • Szerlip P
      • Walters BC
      • et al.
      Obese (Body Mass Index >30) patients have greater functional improvement and reach equivalent outcomes at 12 months following decompression surgery for symptomatic lumbar stenosis.
      ]. Bohl et al. demonstrated increased need for revision surgeries in patients with greater BMI, and lastly, Wilson et al. demonstrated that increased BMI was associated with increased postoperative disability in patients undergoing surgery for degenerative cervical myelopathy [
      • Bohl DD
      • Ahn J
      • Mayo BC
      • Massel DH
      • Tabaraee E
      • Sershon RA
      • et al.
      Does greater body mass index increase the risk for revision procedures following a single-level minimally invasive lumbar discectomy?.
      ,
      • Wilson JR
      • Tetreault LA
      • Schroeder G
      • Harrop JS
      • Prasad S
      • Vaccaro A
      • et al.
      Impact of elevated body mass index and obesity on long-term surgical outcomes for patients with degenerative cervical myelopathy.
      ].
      It is unclear whether obese patients undergoing surgery experience greater weight loss postoperatively. Joseph at al. demonstrated that patients undergoing a successful TLIF procedure with improved function and pain scores did not have significant change in weight postoperatively [
      • Joseph JR
      • Farooqui Z
      • Smith BW
      • Kahn EN
      • Liu X
      • La Marca F
      • et al.
      Does clinical improvement of symptomatic degenerative lumbar disease impact obesity?.
      ]. Akins et al., however, demonstrated that obese and extremely obese patients undergoing lumbar spine fusions experienced more significant weight loss compared with nonobese patients, perhaps due to improvements in back pain and increased physical activity, or perhaps due to the fact they had more excess weight to lose [
      • Akins PT
      • Inacio MCS
      • Bernbeck JA
      • Harris J
      • Chen YX
      • Prentice HA
      • et al.
      Do obese and extremely obese patients lose weight after lumbar spine fusions? Analysis of a cohort of 7303 patients from the kaiser national spine registry.
      ].
      It is important to note that not all studies demonstrate significant differences between obese and nonobese patients. Pereira et al. found no differences in surgical site infections, surgical complications, and reoperation rates due to BMI in the setting of degenerative lumbar spine disease [
      • Pereira BJA
      • De Holanda CV
      • Ribeiro CA
      • De Moura SM
      • Galvo PE
      • Quidute BSQ
      • et al.
      Impact of body mass index in spinal surgery for degenerative lumbar spine disease.
      ]. Buerba et al. did not find increased complication rates after anterior or posterior cervical fusion in the 30-day postoperative period with larger BMI, a conclusion echoed by Narain et al. demonstrating comparable surgical outcomes, narcotics consumption, and hospital costs among different BMI classes undergoing anterior cervical discectomy and fusion [
      • Buerba R a
      • Fu MC
      • Grauer JN
      Anterior and posterior cervical fusion in patients with high body mass index are not associated with greater complications.
      ,
      • Narain AS
      • Hijji FY
      • Haws BE
      • Kudaravalli KT
      • Yom KH
      • Markowitz J
      • et al.
      Impact of body mass index on surgical outcomes, narcotics consumption, and hospital costs following anterior cervical discectomy and fusion.
      ]. Lingutla et al. performed a systematic review and meta-analysis of lumbar spine fusion in obese and nonobese patients and found no difference in pain and functional outcomes [
      • Lingutla KK
      • Pollock R
      • Benomran E
      • Purushothaman B
      • Kasis A
      • Bhatia CK
      • et al.
      Outcome of lumbar spinal fusion surgery in obese patients: a systematic review and meta-Analysis.
      ]. Chotai et al. studied the effect of obesity on cost per quality-adjusted life years gained following anterior cervical discectomy and fusion surgery in elective degenerative pathology; the authors found no significant differences in postdischarge health-care resource utilization, direct cost, indirect cost, and total cost between obese and nonobese patients at postoperative 1-year and 2-year follow-up [
      • Chotai S
      • Sielatycki JA
      • Parker SL
      • Sivaganesan A
      • Kay HL
      • Stonko DP
      • et al.
      Effect of obesity on cost per quality-adjusted life years gained following anterior cervical discectomy and fusion in elective degenerative pathology.
      ]. Finally, several studies demonstrate similar outcomes between obese and nonobese patients when utilizing minimally invasive techniques [
      • Wang T
      • Han C
      • Jiang H
      • Tian P
      The effect of obesity on clinical outcomes after minimally invasive surgery of the spine: a systematic review and meta-analysis.
      ,

      Park P, Upadhyaya C, Garton HJ FK. The Impact of Minimally Invasive spine surgery on perioperative complications in overweight or obese patients. Neurosurgery 2008;62(3):693–9. Discussion 693–9 2008;62:693–9. https://doi.org/10.1227/01.NEU.0000297115.62323.CE.

      ,
      • Senker W
      • Stefanits H
      • Gmeiner M
      • Trutschnig W
      • Weinfurter I
      • Gruber A
      Does obesity affect perioperative and postoperative morbidity and complication rates after minimal access spinal technologies in surgery for lumbar degenerative disc disease.
      ].
      The ability to compensate for positive sagittal malalignment is different between obese and nonobese patients, with the obese population employing lower extremity compensatory mechanisms as opposed to pelvic mechanisms [
      • Jalai CM
      • Diebo BG
      • Cruz DL
      • Poorman GW
      • Vira S
      • Buckland AJ
      • et al.
      The impact of obesity on compensatory mechanisms in response to progressive sagittal malalignment.
      ]. Different compensatory mechanisms, in addition to various comorbidities often associated with obesity, may be just some of the reasons the obese and nonobese populations have different responses to surgery, all factors the spine surgeon must be cognizant of. MIS (eg, via tubular systems) or percutaneous techniques—by decreasing the amount of surgical incision, dead space, and potential paraspinal muscle damage via retraction—may decrease blood loss, accelerate postoperative recovery and mobilization, hospital stay, and overall perioperative morbidity [
      • Stevens KJ
      • Spenciner DB
      • Griffiths KL
      • Kim KD
      • Zwienenberg-Lee M
      • Alamin T
      • et al.
      Comparison of minimally invasive and conventional open posterolateral lumbar fusion using magnetic resonance imaging and retraction pressure studies.
      ,
      • Park Y
      • Ha JW
      Comparison of one-level posterior lumbar interbody fusion performed with a minimally invasive approach or a traditional open approach.
      ,
      • Ntoukas V
      • Muller A
      Minimally invasive approach versus traditional open approach for one level posterior lumbar interbody fusion.
      ,
      • Scheufler K-M
      • Dohmen H
      • Vougioukas VI
      Percutaneous transforaminal lumbar interbody fusion for the treatment of degenerative lumbar instability.
      ]. As such, the authors propose that if spine surgery is indicated on an obese patient and bariatric surgery is not an option or has already been utilized, that anterior cervical or MIS/percutaneous approaches be employed when reasonable (Fig. 4). Fig. 5 summarizes the various ways to mitigate preoperative, intraoperative, and postoperative challenges when caring for obese patients.
      Fig 4
      Fig. 4Flow sheet depicting a general decision tree regarding an obese patient who presents with spine pathology.
      Fig 5
      Fig. 5Maximizing surgical outcomes in obese patients: various ways to mitigate preoperative, intraoperative, and postoperative challenges.

      Conclusions

      Obese patients present several challenges to the spine surgeon. Certain precautions can be undertaken preoperatively, intraoperatively, and postoperatively to mitigate the associated risks to and to optimize outcomes.

      Acknowledgments

      Research reported in this manuscript was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number 2U54GM104942-02 . The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health .

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