Commentary on: “Underweight patients are an often under looked ‘at risk’ population after undergoing posterior cervical spine surgery”

In this edition of NASSJ, we highlight the results of a large database study exploring the impact of low body mass index (BMI) upon surgical outcomes after posterior cervical surgery [[1]Ottesen TD Bagi PS Malpani R. Galivanche AR Varthi AG. Grauer JN. Underweight Patients are an Often Under Looked “At Risk” Population After Undergoing Posterior Cervical Spine Surgery.North American Spine Society Journal (NASSJ). 2020; https://doi.org/10.1016/j.xnsj.2020.100042Google Scholar]. The authors queried the National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2016 and identified 16,806 patients who were submitted to elective posterior cervical spine surgery.After controlling for demographics and overall health status, the results of risk-adjusted multivariate regressions demonstrated that underweight patients (BMI <18.5 kg/m) had the highest risk among all others groups in the BMI spectrum for multiple perioperative complications including adverse events, post-operative infection and reoperation. Perhaps somewhat surprisingly, the impact of low BMI upon complication rates was even greater than those of morbid obesity (BMI >50.0 kg/m2), which, similarly to what has been previously demonstrated by other groups, was associated only with increased risks of perioperative infection [[2]Sridharan M. Malik A.T. Kim J. Khan S.N. Yu E. Does increasing body mass index correlate with adverse outcomes following posterior cervical fusions?.World Neurosurg. 2020; 133 (Epub 2019 Oct 9. PMID:31605849): e789-e795https://doi.org/10.1016/j.wneu.2019.10.011Crossref PubMed Scopus (6) Google Scholar].Nevertheless, it is important to emphasize that the concept of “obesity paradox” (i.e. the observation that patients with high BMI may fare better than those with normal or lower ones) [[3]Curtis J.P. Selter J.G. Wang Y. Rathore S.S. Jovin I.S. Jadbabaie F. Kosiborod M. Portnay E.L. Sokol S.I. Bader F. Krumholz H.M. The obesity paradox: body mass index and outcomes in patients with heart failure.Arch Intern Med. 2005; 165 (Erratum in: Arch Intern Med. 2008;168(6):567. PMID:15642875): 55-61https://doi.org/10.1001/archinte.165.1.55Crossref PubMed Scopus (646) Google Scholar,[4]Badheka A.O. Rathod A. Kizilbash M.A. Garg N. Mohamad T. Afonso L. Jacob S. Influence of obesity on outcomes in atrial fibrillation: yet another obesity paradox.Am J Med. 2010; 123 (PMID:20609687): 646-651https://doi.org/10.1016/j.amjmed.2009.11.026Abstract Full Text Full Text PDF PubMed Scopus (149) Google Scholar, which has led to descriptions such as “metabolically healthy obesity” or “fat but fit”, has been recently been put into question on the grounds that the observed effects might well have been the result of a combination of methodological flaws in earlier studies on the topic including, but not restricted to, the crudeness of BMI as an isolated measure of obesity, confounding, selection and detection bias, reverse causality, and the so-called collider bias [[5]Lennon H. Sperrin M. Badrick E. Renehan A.G. The obesity paradox in cancer: a review.Curr Oncol Rep. 2016; 18 (PMID:27475805; PMCID: PMC4967417): 56https://doi.org/10.1007/s11912-016-0539-4Crossref PubMed Scopus (248) Google Scholar]. It should be emphasized that the “obesity paradox” “obesity”, initially described in cardiovascular diseases but later explored in the realm of oncology [[6]Tsang N.M. Pai P.C. Chuang C.C. Chuang W.C. Tseng C.K. Chang K.P. et al.Overweight and obesity predict better overall survivalrates in cancer patients with distant metastases.Cancer Med. 2016; 5 (Published online 2016 Jan 26): 665-675https://doi.org/10.1002/cam4.634Crossref PubMed Scopus (45) Google Scholar] as well in chronic systemic diseases [[7]Doshi M. Streja E. Rhee C.M. Park J. Ravel V.A. Soohoo M. et al.Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis.Nephrol, Dialysis, Transpl. 2016; 31: 1310-1319Crossref PubMed Scopus (37) Google Scholar], has never been demonstrated in the field of spine surgery [[8]Jiang J. Teng Y. Fan Z. Khan S. Xia Y. Does obesity affect the surgical outcome and complication rates of spinal surgery? A meta-analysis.Clin Orthop Relat Res. 2014; 472 (Epub 2013 Oct 22. PMID:24146361; PMCID: PMC3916601): 968-975https://doi.org/10.1007/s11999-013-3346-3Crossref PubMed Scopus (110) Google Scholar].So far, the vast majority of the scientific literature on the impact of BMI upon surgical outcomes after spine surgery has focused on the deleterious effects of obesity and morbid obesity [9Kalanithi P.A. Arrigo R. Boakye M. Morbid obesity increases cost and complication rates in spinal arthrodesis.Spine (Phila Pa 1976). 2012; 37 (PMID:22037526): 982-988https://doi.org/10.1097/BRS.0b013e31823bbeefCrossref PubMed Scopus (135) Google Scholar, 10Zhang G.A. Zhang W.P. Chen Y.C. Hou Y. Qu W. Ding L.X. Impact of elevated body mass index on surgical outcomes for patients undergoing cervical fusion procedures: a systematic review and meta-analysis.Orthop Surg. 2020; 12 (Epub 2019 Dec 27. PMID:31880083; PMCID: PMC7031590): 3-15https://doi.org/10.1111/os.12572Crossref PubMed Scopus (7) Google Scholar, 11Phan K. Kothari P. Lee N.J. Virk S. Kim J.S. Cho S.K. Impact of obesity on outcomes in adults undergoing elective posterior cervical fusion.Spine (Phila Pa 1976). 2017; 42 (PMID:28207668): 261-266https://doi.org/10.1097/BRS.0000000000001711Crossref PubMed Scopus (34) Google Scholar]. A few studies in other specialties have suggested that underweight patients may display higher rates of unfavorable outcomes, especially after oncological surgeries [[12]Zhao B. Zhang J. Zhang J. Zou S. Luo R. Xu H. Huang B. The impact of preoperative underweight status on postoperative complication and survival outcome of gastric cancer patients: a systematic review and meta-analysis.Nutr Cancer. 2018; 70 (Epub 2019 Jan 26. PMID:30686045): 1254-1263https://doi.org/10.1080/01635581.2018.1559937Crossref PubMed Scopus (16) Google Scholar,[13]Swalarz M. Swalarz G. Juszczak K. Maciukiewicz P. Czurak K. Matuszewski M. Gajewska D. Słojewski M. Bogacki R. Bryniarski P. Paradysz A. Kadłubowski M. Drewa T. Genge E. Correlation between malnutrition, body mass index and complications in patients with urinary bladder cancer who underwent radical cystectomy.Adv Clin Exp Med. 2018; 27 (PMID:30019864): 1141-1147https://doi.org/10.17219/acem/89863Crossref PubMed Scopus (8) Google Scholar As one of the first well-conducted studies highlighting the impact of low BMI upon complications rates after spine surgery, we believe the results of this study are definitely worthy of attention, especially taking into account the extensive efforts in the recent literature toward developing measures to quantify frailty as well as to evaluate its impact upon surgical outcomes after spine surgery [[14]Flexman A.M. Charest-Morin R. Stobart L. Street J. Ryerson C.J. Frailty and postoperative outcomes in patients undergoing surgery for degenerative spine disease.Spine J. 2016; 16 (Epub 2016 Jun 30. PMID:27374110): 1315-1323https://doi.org/10.1016/j.spinee.2016.06.017Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar,[15]Ali R. Schwalb J.M. Nerenz D.R. Antoine H.J. Rubinfeld I. Use of the modified frailty index to predict 30-day morbidity and mortality from spine surgery.J Neurosurg Spine. 2016; 25 (Epub 2016 May 6. PMID:27153143): 537-541https://doi.org/10.3171/2015.10.SPINE14582Crossref PubMed Scopus (148) Google Scholar.There are obviously some methodological limitations, such as the lack of more granular clinical data, a problem which seems to be inherent to such type of large database study. In terms of interpreting the obtained results, although it is true that this study demonstrated an association between low BMI and perioperative adverse events, infections and re-operations rates after posterior cervical spine surgery, any possible attempts to establish a causative role between low BMI and such adverse events should be tempered by the possibility of confounding factors.For instance, it has already demonstrated that poor nutritional status (as measured by the prognostic nutritional index - PNI) [[16]Oe S. Yamato Y. Hasegawa T. Yoshida G. Kobayashi S. Yasuda T. Banno T. Arima H. Mihara Y. Ushirozako H. Yamada T. Ide K. Watanabe Y. Matsuyama Y. Association between a prognostic nutritional index less than 50 and the risk of medical complications after adult spinal deformity surgery.J Neurosurg Spine. 2020; 1-6 (Epub ahead of print. PMID:32217806)https://doi.org/10.3171/2020.1.SPINE191410Crossref Scopus (6) Google Scholar] as well as low albumin are associated with increased risks of wound infection after spine surgery [[17]Kumar S. van Popta D. Rodrigues-Pinto R. et al.Risk factors for wound infection in surgery for spinal metastasis.Eur Spine J. 2015; 24: 528-532https://doi.org/10.1007/s00586-013-3127-4Crossref PubMed Scopus (22) Google Scholar,[18]Salvetti D.J. Tempel Z.J. Goldschmidt E. et al.Low preoperative serum prealbumin levels and the postoperative surgical site infection risk in elective spine surgery: a consecutive series.J Neurosurg Spine. 2018; 29: 549-552https://doi.org/10.3171/2018.3.SPINE171183Crossref PubMed Scopus (24) Google Scholar. As one could naturally expect some degree of correlation between body weight, nutritional status and albumin levels, it might well be the case that, when adjusting for albumin levels and lymphocyte count (the other variable employed to calculate the PNI), low BMI per se may not play a significant role in predicting perioperative adverse events.Similarly, considering the possible association between low BMI and decreased bone mineral density (BMD) as well as the extensive literature on the impact of osteopenia and osteoporosis upon complication rates after spinal fusion [[19]Liu Y. Dash A. Krez A. Kim H.J. Cunningham M. Schwab F. Hughes A. Carlson B. Samuel A. Marty E. Moore H. McMahon D.J. Carrino J.A. Bockman R.S. Stein E.M. Low volumetric bone density is a risk factor for early complications after spine fusion surgery.Osteoporos Int. 2020; 31 (Epub 2020 Jan 9. PMID:31919536.10): 647-654https://doi.org/10.1007/s00198-019-05245-7Crossref PubMed Scopus (15) Google Scholar,[20]Gupta A. Cha T. Schwab J. Fogel H. Tobert D. Razi A.E. Hecht A. Bono C.M. Hershman S. Osteoporosis increases the likelihood of revision surgery following a long spinal fusion for adult spinal deformity.Spine J. 2020; 10 (S1529-9430(20)31010-XEpub ahead of print. PMID:32791242)https://doi.org/10.1016/j.spinee.2020.08.002Abstract Full Text Full Text PDF Scopus (11) Google Scholar, it is highly recommended that future studies on the topic consider bone quality in their multivariate analysis.Finally, several studies in the literature have suggested an association between nicotine consumption and low BMI [[21]Stavropoulos-Kalinoglou A. Metsios G.S. Panoulas V.F. Douglas K.M. Nevill A.M. Jamurtas A.Z. Kita M. Koutedakis Y. Kitas G.D. Cigarette smoking associates with body weight and muscle mass of patients with rheumatoid arthritis: a cross-sectional, observational study.Arthritis Res Ther. 2008; 10 (Epub 2008 May 20. PMID:18492239; PMCID: PMC2483449): R59https://doi.org/10.1186/ar2429Crossref PubMed Scopus (33) Google Scholar], as well as between smoking cessation and weight gain [[22]Nicklas B.J. Tomoyasu N. Muir J. Goldberg A.P. Effects of cigarette smoking and its cessation on body weight and plasma leptin levels.Metabolism. 1999; 48 (PMID:10381158): 804-808https://doi.org/10.1016/s0026-0495(99)90183-xAbstract Full Text PDF PubMed Scopus (0) Google Scholar]. Considering the well-established association between smoking status and poor surgical outcomes and complications rates in spine surgery [[23]Jackson 2nd, K.L. Devine J.G. The effects of smoking and smoking cessation on spine surgery: a systematic review of the literature.Global Spine J. 2016; 6 (Epub 2016 Jan 15. PMID:27781190; PMCID: PMC5077710): 695-701https://doi.org/10.1055/s-0036-1571285Crossref PubMed Scopus (68) Google Scholar], future studies should also control for such a factor, as the current study published in NASSJ actually did.Ultimately, although this commendable study which NASSJ is honored to publish constitutes an important step toward properly identifying a still largely underrecognized problem (i.e. the deleterious effects of low BMI upon surgical outcomes after spine surgery), additional research is necessary in order to both confirm the observed findings in other clinical series as well as to properly unveil the possible underlying pathophysiological mechanisms which may the association of low BMI and increased rates of perioperative complications and adverse events after spine In this edition of NASSJ, we highlight the results of a large database study exploring the impact of low body mass index (BMI) upon surgical outcomes after posterior cervical surgery [[1]Ottesen TD Bagi PS Malpani R. Galivanche AR Varthi AG. Grauer JN. Underweight Patients are an Often Under Looked “At Risk” Population After Undergoing Posterior Cervical Spine Surgery.North American Spine Society Journal (NASSJ). 2020; https://doi.org/10.1016/j.xnsj.2020.100042Google Scholar]. The authors queried the National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2016 and identified 16,806 patients who were submitted to elective posterior cervical spine After controlling for demographics and overall health status, the results of risk-adjusted multivariate regressions demonstrated that underweight patients (BMI <18.5 kg/m) had the highest risk among all others groups in the BMI spectrum for multiple perioperative complications including adverse events, post-operative infection and reoperation. Perhaps somewhat surprisingly, the impact of low BMI upon complication rates was even greater than those of morbid obesity (BMI >50.0 kg/m2), which, similarly to what has been previously demonstrated by other groups, was associated only with increased risks of perioperative infection [[2]Sridharan M. Malik A.T. Kim J. Khan S.N. Yu E. Does increasing body mass index correlate with adverse outcomes following posterior cervical fusions?.World Neurosurg. 2020; 133 (Epub 2019 Oct 9. PMID:31605849): e789-e795https://doi.org/10.1016/j.wneu.2019.10.011Crossref PubMed Scopus (6) Google Scholar]. it is important to emphasize that the concept of “obesity paradox” (i.e. the observation that patients with high BMI may fare better than those with normal or lower ones) [[3]Curtis J.P. Selter J.G. Wang Y. Rathore S.S. Jovin I.S. Jadbabaie F. Kosiborod M. Portnay E.L. Sokol S.I. Bader F. Krumholz H.M. The obesity paradox: body mass index and outcomes in patients with heart failure.Arch Intern Med. 2005; 165 (Erratum in: Arch Intern Med. 2008;168(6):567. PMID:15642875): 55-61https://doi.org/10.1001/archinte.165.1.55Crossref PubMed Scopus (646) Google Scholar,[4]Badheka A.O. Rathod A. Kizilbash M.A. Garg N. Mohamad T. Afonso L. Jacob S. Influence of obesity on outcomes in atrial fibrillation: yet another obesity paradox.Am J Med. 2010; 123 (PMID:20609687): 646-651https://doi.org/10.1016/j.amjmed.2009.11.026Abstract Full Text Full Text PDF PubMed Scopus (149) Google Scholar, which has led to descriptions such as “metabolically healthy obesity” or “fat but fit”, has been recently been put into question on the grounds that the observed effects might well have been the result of a combination of methodological flaws in earlier studies on the topic including, but not restricted to, the crudeness of BMI as an isolated measure of obesity, confounding, selection and detection bias, reverse causality, and the so-called collider bias [[5]Lennon H. Sperrin M. Badrick E. Renehan A.G. The obesity paradox in cancer: a review.Curr Oncol Rep. 2016; 18 (PMID:27475805; PMCID: PMC4967417): 56https://doi.org/10.1007/s11912-016-0539-4Crossref PubMed Scopus (248) Google Scholar]. It should be emphasized that the “obesity paradox” “obesity”, initially described in cardiovascular diseases but later explored in the realm of oncology [[6]Tsang N.M. Pai P.C. Chuang C.C. Chuang W.C. Tseng C.K. Chang K.P. et al.Overweight and obesity predict better overall survivalrates in cancer patients with distant metastases.Cancer Med. 2016; 5 (Published online 2016 Jan 26): 665-675https://doi.org/10.1002/cam4.634Crossref PubMed Scopus (45) Google Scholar] as well in chronic systemic diseases [[7]Doshi M. Streja E. Rhee C.M. Park J. Ravel V.A. Soohoo M. et al.Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis.Nephrol, Dialysis, Transpl. 2016; 31: 1310-1319Crossref PubMed Scopus (37) Google Scholar], has never been demonstrated in the field of spine surgery [[8]Jiang J. Teng Y. Fan Z. Khan S. Xia Y. Does obesity affect the surgical outcome and complication rates of spinal surgery? A meta-analysis.Clin Orthop Relat Res. 2014; 472 (Epub 2013 Oct 22. PMID:24146361; PMCID: PMC3916601): 968-975https://doi.org/10.1007/s11999-013-3346-3Crossref PubMed Scopus (110) Google Scholar]. far, the vast majority of the scientific literature on the impact of BMI upon surgical outcomes after spine surgery has focused on the deleterious effects of obesity and morbid obesity [9Kalanithi P.A. Arrigo R. Boakye M. Morbid obesity increases cost and complication rates in spinal arthrodesis.Spine (Phila Pa 1976). 2012; 37 (PMID:22037526): 982-988https://doi.org/10.1097/BRS.0b013e31823bbeefCrossref PubMed Scopus (135) Google Scholar, 10Zhang G.A. Zhang W.P. Chen Y.C. Hou Y. Qu W. Ding L.X. Impact of elevated body mass index on surgical outcomes for patients undergoing cervical fusion procedures: a systematic review and meta-analysis.Orthop Surg. 2020; 12 (Epub 2019 Dec 27. PMID:31880083; PMCID: PMC7031590): 3-15https://doi.org/10.1111/os.12572Crossref PubMed Scopus (7) Google Scholar, 11Phan K. Kothari P. Lee N.J. Virk S. Kim J.S. Cho S.K. Impact of obesity on outcomes in adults undergoing elective posterior cervical fusion.Spine (Phila Pa 1976). 2017; 42 (PMID:28207668): 261-266https://doi.org/10.1097/BRS.0000000000001711Crossref PubMed Scopus (34) Google Scholar]. A few studies in other specialties have suggested that underweight patients may display higher rates of unfavorable outcomes, especially after oncological surgeries [[12]Zhao B. Zhang J. Zhang J. Zou S. Luo R. Xu H. Huang B. The impact of preoperative underweight status on postoperative complication and survival outcome of gastric cancer patients: a systematic review and meta-analysis.Nutr Cancer. 2018; 70 (Epub 2019 Jan 26. PMID:30686045): 1254-1263https://doi.org/10.1080/01635581.2018.1559937Crossref PubMed Scopus (16) Google Scholar,[13]Swalarz M. Swalarz G. Juszczak K. Maciukiewicz P. Czurak K. Matuszewski M. Gajewska D. Słojewski M. Bogacki R. Bryniarski P. Paradysz A. Kadłubowski M. Drewa T. Genge E. Correlation between malnutrition, body mass index and complications in patients with urinary bladder cancer who underwent radical cystectomy.Adv Clin Exp Med. 2018; 27 (PMID:30019864): 1141-1147https://doi.org/10.17219/acem/89863Crossref PubMed Scopus (8) Google Scholar As one of the first well-conducted studies highlighting the impact of low BMI upon complications rates after spine surgery, we believe the results of this study are definitely worthy of attention, especially taking into account the extensive efforts in the recent literature toward developing measures to quantify frailty as well as to evaluate its impact upon surgical outcomes after spine surgery [[14]Flexman A.M. Charest-Morin R. Stobart L. Street J. Ryerson C.J. Frailty and postoperative outcomes in patients undergoing surgery for degenerative spine disease.Spine J. 2016; 16 (Epub 2016 Jun 30. PMID:27374110): 1315-1323https://doi.org/10.1016/j.spinee.2016.06.017Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar,[15]Ali R. Schwalb J.M. Nerenz D.R. Antoine H.J. Rubinfeld I. Use of the modified frailty index to predict 30-day morbidity and mortality from spine surgery.J Neurosurg Spine. 2016; 25 (Epub 2016 May 6. PMID:27153143): 537-541https://doi.org/10.3171/2015.10.SPINE14582Crossref PubMed Scopus (148) Google Scholar. are obviously some methodological limitations, such as the lack of more granular clinical data, a problem which seems to be inherent to such type of large database study. In terms of interpreting the obtained results, although it is true that this study demonstrated an association between low BMI and perioperative adverse events, infections and re-operations rates after posterior cervical spine surgery, any possible attempts to establish a causative role between low BMI and such adverse events should be tempered by the possibility of confounding instance, it has already demonstrated that poor nutritional status (as measured by the prognostic nutritional index - PNI) [[16]Oe S. Yamato Y. Hasegawa T. Yoshida G. Kobayashi S. Yasuda T. Banno T. Arima H. Mihara Y. Ushirozako H. Yamada T. Ide K. Watanabe Y. Matsuyama Y. Association between a prognostic nutritional index less than 50 and the risk of medical complications after adult spinal deformity surgery.J Neurosurg Spine. 2020; 1-6 (Epub ahead of print. PMID:32217806)https://doi.org/10.3171/2020.1.SPINE191410Crossref Scopus (6) Google Scholar] as well as low albumin are associated with increased risks of wound infection after spine surgery [[17]Kumar S. van Popta D. Rodrigues-Pinto R. et al.Risk factors for wound infection in surgery for spinal metastasis.Eur Spine J. 2015; 24: 528-532https://doi.org/10.1007/s00586-013-3127-4Crossref PubMed Scopus (22) Google Scholar,[18]Salvetti D.J. Tempel Z.J. Goldschmidt E. et al.Low preoperative serum prealbumin levels and the postoperative surgical site infection risk in elective spine surgery: a consecutive series.J Neurosurg Spine. 2018; 29: 549-552https://doi.org/10.3171/2018.3.SPINE171183Crossref PubMed Scopus (24) Google Scholar. As one could naturally expect some degree of correlation between body weight, nutritional status and albumin levels, it might well be the case that, when adjusting for albumin levels and lymphocyte count (the other variable employed to calculate the PNI), low BMI per se may not play a significant role in predicting perioperative adverse considering the possible association between low BMI and decreased bone mineral density (BMD) as well as the extensive literature on the impact of osteopenia and osteoporosis upon complication rates after spinal fusion [[19]Liu Y. Dash A. Krez A. Kim H.J. Cunningham M. Schwab F. Hughes A. Carlson B. Samuel A. Marty E. Moore H. McMahon D.J. Carrino J.A. Bockman R.S. Stein E.M. Low volumetric bone density is a risk factor for early complications after spine fusion surgery.Osteoporos Int. 2020; 31 (Epub 2020 Jan 9. PMID:31919536.10): 647-654https://doi.org/10.1007/s00198-019-05245-7Crossref PubMed Scopus (15) Google Scholar,[20]Gupta A. Cha T. Schwab J. Fogel H. Tobert D. Razi A.E. Hecht A. Bono C.M. Hershman S. Osteoporosis increases the likelihood of revision surgery following a long spinal fusion for adult spinal deformity.Spine J. 2020; 10 (S1529-9430(20)31010-XEpub ahead of print. PMID:32791242)https://doi.org/10.1016/j.spinee.2020.08.002Abstract Full Text Full Text PDF Scopus (11) Google Scholar, it is highly recommended that future studies on the topic consider bone quality in their multivariate several studies in the literature have suggested an association between nicotine consumption and low BMI [[21]Stavropoulos-Kalinoglou A. Metsios G.S. Panoulas V.F. Douglas K.M. Nevill A.M. Jamurtas A.Z. Kita M. Koutedakis Y. Kitas G.D. Cigarette smoking associates with body weight and muscle mass of patients with rheumatoid arthritis: a cross-sectional, observational study.Arthritis Res Ther. 2008; 10 (Epub 2008 May 20. PMID:18492239; PMCID: PMC2483449): R59https://doi.org/10.1186/ar2429Crossref PubMed Scopus (33) Google Scholar], as well as between smoking cessation and weight gain [[22]Nicklas B.J. Tomoyasu N. Muir J. Goldberg A.P. Effects of cigarette smoking and its cessation on body weight and plasma leptin levels.Metabolism. 1999; 48 (PMID:10381158): 804-808https://doi.org/10.1016/s0026-0495(99)90183-xAbstract Full Text PDF PubMed Scopus (0) Google Scholar]. Considering the well-established association between smoking status and poor surgical outcomes and complications rates in spine surgery [[23]Jackson 2nd, K.L. Devine J.G. The effects of smoking and smoking cessation on spine surgery: a systematic review of the literature.Global Spine J. 2016; 6 (Epub 2016 Jan 15. PMID:27781190; PMCID: PMC5077710): 695-701https://doi.org/10.1055/s-0036-1571285Crossref PubMed Scopus (68) Google Scholar], future studies should also control for such a factor, as the current study published in NASSJ actually although this commendable study which NASSJ is honored to publish constitutes an important step toward properly identifying a still largely underrecognized problem (i.e. the deleterious effects of low BMI upon surgical outcomes after spine surgery), additional research is necessary in order to both confirm the observed findings in other clinical series as well as to properly unveil the possible underlying pathophysiological mechanisms which may the association of low BMI and increased rates of perioperative complications and adverse events after spine The authors that have or that could have to the in this Underweight patients are an “At after undergoing posterior cervical spine American Spine Society Journal (BMI) is a that is to quantify mass and weight studies have focused on the association of high BMI on spine surgery outcomes and variable results may have to or of BMI groups or few studies have outcomes of patients with low The of the current study was to patients the of the BMI spectrum and to establish granular BMI for which patients risk for complication and mortality following posterior cervical spine PDF

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