442 pissn : 1226-2102, eissn : 2005-8918 Original Article J Korean Orthop Assoc 2017; 52: 442-447 https://doi.org/10.4055/jkoa.2017.52.5.442 www.jkoa.org 요추극외측추간판탈출증과후외측추간판탈출증의수술에대한상대위험도 : 후향적코호트연구 하대호 심대무 * 김태균 * 오성균 김진 원광대학교의과대학산본병원정형외과, * 원광대학교의과대학정형외과학교실, 원광의과학연구소 Relative Risk of Operation between Lumbar Far Lateral Disc Herniation and Posterolateral Disc Herniation: A Retrospective Cohort Study Dae Ho Ha, M.D., Dae Moo Shim, M.D.*, Tae Kyun Kim, M.D.*, Sung Kyun Oh, M.D., and Jin Kim, M.D. Department of Orthopaedic Surgery, Wonkwang University Sanbon Hospital, Gunpo, *Department of Orthopaedic Surgery and Institute of Wonkwang Medical Science, Wonkwang University School of Medicine, Iksan, Korea Purpose: We reported relative risk of operation between patients who were diagnosed with lumbar far lateral disc herniation and posterolateral disc herniation after transforaminal epidural block. Materials and Methods: A retrospective cohort study was performed on 295 patients (131 male and 164 female) who underwent transforaminal epidural block for unilateral radiculopathy caused by lumbar intervertebral disc herniation. Among these 295 patients, 34 patients were diagnosed with far lateral disc herniation and 261 patients with posterolateral disc herniation. The median follow-up period was 23.9 months, with an average age of 55.7 years. Results: Fifty-one patients underwent surgical treatment. Among them, 38 patients had posterolateral disc herniation and 13 patients had far lateral disc herniation. Patients with far lateral disc herniation, when compared with posterolateral disc herniation, had a relative risk of operation of 2.67 (1.59-4.48, 95% confidence interval) with statistical significance (p=0.0002). At the final follow-up, the average visual analogue scale (VAS) score for radicular pain in the surgical and non-surgical groups was 0.69 and 1.50, respectively; the average Korean- Oswestry Disability Questionnaire (K-ODI) score was 11.7 and 9.6, respectively. The difference of average VAS score showed a statistical significance (p=0.035), however, that of K-ODI showed no statistical significance (p=0.266). Conclusion: In the case of far lateral disc herniation, the relative risk of surgery after transforaminal epidural block was 2.67, which is higher than that of posterolateral disc herniation. Therefore, we should consider surgical treatment more aggressively. Key words: spine, discectomy, epidural injections 서론 Received November 25, 2016 Revised January 3, 2017 Accepted March 20, 2017 Correspondence to: Sung Kyun Oh, M.D. Department of Orthopaedic Surgery, Wonkwang University Sanbon Hospital, 327 Sanbon-ro, Gunpo 15865, Korea TEL: +82-31-390-2224 FAX: +82-31-398-2223 E-mail: niceo@hanmail.net *This research was supported by grant from Wonkwang University, 2017. 극외측추간판탈출증은추간판이추간공혹은추간공외측으로탈출하는것으로측방또는극측방추간판탈출증이라고도불린다. 1) 전체추간판탈출증의 7%-12% 를차지한다고알려져있으나과거보다발달된영상기술로진단이어렵거나놓치는경우는거의없다. 2,3) 특징적인임상증상을가지고있으나후방혹은후측방추간판탈출증과동일하게비수술적치료에도호전이없거나 The Journal of the Korean Orthopaedic Association Volume 52 Number 5 2017 Copyright 2017 by The Korean Orthopaedic Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
443 Relative Risk of Operation for Lumbar Far Lateral Disc Herniation 실패했을때수술적치료를시행하는것이근간이나통증이극심하고신경학적이상소견이저명하여일반적인후측방추간판탈출증같은척추관내추간판탈출증의자연경과와는다를것으로생각된다. 그러나일반적인척추관내추간판탈출증과는달리극외측추간판탈출증의자연경과에대해서는거의알려져있지않으며대증치료로성공할확률역시 10% 에서 71% 까지다양하게알려져있다. 2,4,5) 본연구는극외측추간판탈출증환자에대해서후향적코호트연구를시행하고일반적인후방혹은후외측추간판탈출증환자와비교하여수술에대한상대위험도 (relative risk) 및이들의임상결과에대해서보고하고자한다. 대상및방법 2008년 3월 1일부터 2015년 12월 31일까지요추추간판탈출증으로진단되어원광대학교산본병원정형외과에서일측방사통에대해경추간공하경막외차단술을시행받은 461명의환자를대상으로하였다. 경막외차단술은자기공명영상검사를통해진단된추간판탈출증에의한방사통으로하지직거상검사혹은대퇴신경견인검사에서양성인환자들을대상으로하였고모두수술장에서 C-arm 투시하에시행하였다. 응급실로내원하거나방사통과신경증상으로보행이어려운경우입원후경막외차단술시행을원칙으로하였으며이외의경우외래에서 1주간격으로 3 회시행하였다. 최초시행후 6주, 그리고 3개월, 6개월, 12개월후외래정기방문을원칙으로하였으며외래방문시마다요통과하지방사통에대한시각통증등급 (visual analogue scale, VAS) 평가및 Korean-Oswestry Disability Questionnaire (K-ODI) 평가를시행하였다. 정기적인외래추시를통해 6개월이상외래추시가되는환자를연구대상으로하였으며최종적으로외래경과기록및전화면담을통해수술시행여부를확인하였다. 461명의환자중 166명의환자가중도탈락하였고 295명의환자가연구대상에 해당되었다. 이들은남성 131명, 여성 164명이었고중앙연령값은 55.7세였고중앙추시값은 23.9개월이었다. 요추 45번추간판탈출증이 182예로 61.7% 였고요추 5번 ~ 천추 1번간추간판탈출증은 74예로 25.1% 였으며요추 45번및요추 5번 ~ 천추 1번간두분절이 86.8% 로대부분을차지하였다 (Table 1). 본원혹은타병원에서신경차단술을시행하고 6주이상대증치료에실패한환자나지속적인족하수를포함한보행장애를일으킬정도의하지마비가지속되는경우, 마미증후군이의심되는경우수술적응증으로하였으며추시도중 51명의환자가수술적치료를받았다. 통계분석은 SPSS ver. 12 (SPSS Inc., Chicago, IL, USA) 프로그램을이용하였으며유의수준 p<0.05로하였다. VAS 및 K-ODI 의평균값의비교는정규성을보이지않아 Mann-Whitney U-test 를사용하였다. 상대위험도분석은 Altman 6) 에의한방법으로계산하였다. 결과 295명의환자중추간공혹은극외탈출증으로진단된환자가 34 명이었으며후방혹은후외측탈출증으로진단된경우는 261명이었다. 추시도중수술적치료를시행한 51명중 13예는극외탈출증이었고 38예는후방혹은후외측탈출증이었다 (Fig. 1). 34명의극외측탈출증환자중남성 15명, 여성 19명이었고이들의중앙연령은 61.9세로 55.1세인후방혹은후외측탈출증환자보다약 7세정도더많았고요추 3, 4번추간판탈출증의비율이 18% 로 4-5배높았으나여전히요추 4, 5번에서극외측탈출증의빈도가가장높았다 (Table 2). 후방혹은후외측탈출증으로진단된경우 14.5% 에서, 극외탈출증으로진단된경우는 38.2% 에서수술로이어졌으며이들 13예의경우 2예는경추간공내시경을이용한추간판절제술이 2예, 현미경을이용한추간판절제술이 5예, 경추간공감압및유합술 Table 1. Demographic Data of Patients Variable Value Patient (male/female) 131/164 Mean age (yr) 55.7 Level L1 2 1 L2 3 8 L3 4 30 L4 5 182 L5 S1 74 Mean follow-up (mo) 23.9 Values are presented as number only or mean only. Far lateral disc herniation (n=34) Op + (n=13) Patients (n=295) Op (n=21) Posterior disc herniation (n=261) Op + (n=38) Op (n=223) MRI, P/ex assignment by investigator Follow-up period outcome of interest Figure 1. Results of retrospective cohort. MRI, magnetic resonance imaging; P/ex, physical exam; Op +, operation (+); Op, operation ( ).
444 Dae Ho Ha, et al. Table 2. Results of Each Group Variable Posterolateral (n=261) Far lateral (n=34) Patient (male/female) 116/145 15/19 Mean age (yr) 55.1 61.9 Level L1 2 1 (0.4) 0 (0) L2 3 8 (3.1) 0 (0) L3 4 24 (9.2) 6 (17.6) L4 5 161 (61.7) 21 (61.8) L5 S1 67 (25.7) 7 (20.6) Total 261 (100) 34 (100) Values are presented as number only, mean only, or number (%). Table 3. Relative Risk of Operation for far Lateral Disc Herniation Patients Variable Result Relative risk 2.67 95% CI 1.5872 4.4794 Z statistic 3.705 Significance level p=0.0002 NNT (benefit) 4.185 95% CI 2.699 CI, confidence interval; NNT, number needed to treat. Table 4. Clinical Outcomes of Patients with Lumbar Far Lateral Disc Herniation Patients Operation group Conservative p-value VAS (leg pain) 0.69±0.95 1.50±1.04 0.035 VAS (back pain) 1.46±1.10 1.80±0.95 0.356 K-ODI 11.7±1.4 9.6±1.2 0.266 Values are presented as mean±standard deviation. VAS, visual analogue scale; K-ODI, Korean-Oswestry Disability Questionnaire. 이 6예에서시행되었다. 요추극외측추간판탈출증의수술에대한상대위험도는 2.67 (95% confidence interval, 1.5872-4.4794) 였고 p값은 0.0002로통계적으로유의한값이었다 (Table 3). 요추극외측탈출증으로진단된환자의최종추시방사통에대한 VAS 값의경우수술군에서 0.69±0.95점, 대증치료군에서 1.50±1.04점으로수술군에서낮았으며 (p=0.035), 요통에대한 VAS의경우는수술군에서 1.46± 1.10, 대증치료군에서 1.80±0.95로유의한차이를보이지않았다 (p=0.356). 또한극외탈출증환자의최종추시 K-ODI의경우수술군에서 11.7±1.4, 대증치료군에서 9.6±1.2로오히려수술군에서높았으나통계적으로유의한차이는아니었다 (p=0.266) (Table 4). 고찰 전형적인척추관내추간판탈출증의경우보존적치료에도양호한결과를보여수술적치료로이어지는경우는 10%-26% 로보고되고있다. 7-9) 최근국내에서보고된척추강내 1/3 이상침범한추간판탈출증 39예를대상으로한평균 28개월추시전향적연구에서보존적치료의성공률이 85% 였고 39예중 4예, 즉 10% 에서만수술로의전환이필요하였다고보고한바있다. 7) 그러나극외측탈출증과척추관내추간판탈출증의해부학적특성이다르고더고령에서발생하는차이점이있으므로자연경과나보존적치 료의결과에차이가있을것으로생각된다. 1995년까지도 Epstein 등 2) 은극외탈출증에대한비수술적치료의성공률은 10% 미만으로대부분수술적치료가필요하다고주장하였다. 하지만이후신경차단술을포함한보존적치료의발달로 Weiner와 Fraser 10) 는 30명의환자중 27명이추간공신경차단술후즉각적인통증경감을보여 3명만이수술적치료가필요하다고하였고 Rust와 Olivero 5) 도 17명의극외측추간판탈출증의비수술적치료시 12명은 3년추시에서방사통이소실되어그성공률을 71% 로보고하기도하였다. 국내에서도 Kim 등 11) 은극외측탈출증으로진단된 24명의환자중신경차단술등의보존적치료에실패한 9예 (37.5%) 는수술적으로치료하였다고보고하였다. 12) 이렇듯극외측탈출증역시보존적치료가초기에시도될수있으나심한방사통과동반된신경학적인장애로인해수술적치료로전환되는경우가기존척추관내추간판탈출증보다높을것으로예상할수있다. 극외탈출증에의한신경근압박시에는후방신경절 (dorsal root ganglion) 을직접자극하고추간공내에고정된신경근이압박되어극심한통증과보행장애혹은똑바로눕게하지못하게되는등급성기극심한통증이선행하고이후보행에영향을주는신경학적인결손이나타나게된다. 13,14) 이는본연구에서보듯이요추 3, 4번과 4, 5번분절이환이 80% 이므로출구신경근인요추 3번신경근과 4번신경근이압박되어대퇴및하지의통증과
445 Relative Risk of Operation for Lumbar Far Lateral Disc Herniation 함께대퇴사두군과전방경골근마비를주로초래하기때문이다. 대퇴사두근과전방경골근은무릎과발목관절의대표적인근육으로안정성에중요하므로이들근육의영구적인마비는이차적인관절의문제를일으킬수있다. 또한보행에영향을주는저명한마비역시극심한방사통과함께기존척추관내추간판탈출증보다높은수술비율로이어졌다고생각된다. 또한본연구에서도극외탈출증의평균발생연령이척추관내추간판탈출증보다약 7세가량높았는데이는기존에알려진것과유사하게평균 61.9세였으며, 이는퇴행성변화에의한영향으로섬유륜외측의퇴행성변화와상요추부의시상면배열후관절이추간판에더많은전단력을전달하기때문이라고알려져있다. 2,12,14) 본연구에서도고령의경우동반된협착증과퇴행성불안정성등의이환이더높아수술로이어진경우도있고또한단순감압술보다는유합술을선택하게되는이유가될것으로생각된다. 특히수술한 13예의평균연령은 64세로비수술적치료군보다훨씬고령이었으며, 단순추간판절제술만시행한 7예의경우평균연령은 60세였고유합술을시행한 6예는평균 69세였다. 극외측탈출증치료의결과는중앙값 23.9개월추시에서수술군에서방사통에대한 VAS 값이 0.69, 비수술군에서 1.50으로수술군에서의미있게낮았으나요통에대한 VAS의경우수술군이 1.46으로대증치료군의 1.80보다낮았으나통계적으로의미있는차이를보이지않았고수술후기능결과지표인 K-ODI 값은오히려수술군에서더높았는데이는수술군에서더욱더고령인점과요추부유합술에대한이차적보상성등의편견이작용했을것으로유추해볼수있었다. 또한요통의경우통계적으로의미있는차이를보이지않았으므로대증치료결과와대등하다고해석하기보다는수술군에서요통에대한 VAS값이낮았으나 13예로통계적유의성을검증하기는어렵다고해석하는것이옳다고생각된다. 극외탈출증의해부학적특성으로인한심한통증과신경학적이상, 그리고고령에서의발생이척추관내탈출증보다높은수술비율로이어진것으로보이며수술에대한상대위험도가 2.67배높아진원인중하나인것으로저자는분석하였다. 본연구는극외탈출증에대한보존적치료의결과및척추관내추간판탈출증보다수술위험도가 2.67배이상높다는것을밝힌최초의연구이다. 다만극외측탈출증의발생빈도가높지않아후향적코호트연구방법을선택하여수술에대한상대위험도를구하였으나 461예중 166예가중도탈락하는등중도탈락자비율이 36.0% 로높아중도탈락자의경향에따라편견개입이가능할수도있다. 또한탈락자중증상이심한증례보다는경한증례일가능성이높아척추관내탈출증환자의수술비율을더높일수있는여지도있었다고생각된다. 그러나극외탈출증의경우타병원으로의전원등의사유로 3예 (8.1%) 에서만중도탈락하였으므로극외탈출증의환자의수술비율은편견개입여지가다 소적을것으로추정되었다. 극심한통증으로인해신경차단술에의한호전이있었음에도잔존혹은재발하는통증이심해타병원으로전원을원한증례였다. 따라서척추관내추간판탈출증과는다르게극외탈출증의경우대증치료의기간을 2-3주정도로짧게하고통증조절이안되거나신경학적인이상이지속되는경우적극적인수술적치료를고려할수있도록국내추간판절제술에대한급여기준또한척추관내탈출증과는차이를두어야한다고생각된다. 결론 극외측탈출증의경우후방혹은후외측탈출증보다신경차단술후수술에대한상대위험도가 2.67로높고극외탈출증환자들의수술후방사통감소가대증치료군보다좀더뚜렷했으므로마비가동반되었거나통증이심한경우적극적으로수술을고려해야한다. CONFLICTS OF INTEREST The authors have nothing to disclose. REFERENCES 1. Epstein NE. Foraminal and far lateral lumbar disc herniations: surgical alternatives and outcome measures. Spinal Cord. 2002;40:491-500. 2. Epstein NE. Evaluation of varied surgical approaches used in the management of 170 far-lateral lumbar disc herniations: indications and results. J Neurosurg. 1995;83:648-56. 3. Ahn MW, Kim US, Kim GB. Usefulness of the ProSet MRI for diagnosis of the extraforaminal disc herniation. J Korean Soc Spine Surg. 2013;20:28-33. 4. Epstein NE. Different surgical approaches to far lateral lumbar disc herniations. J Spinal Disord. 1995;8:383-94. 5. Rust MS, Olivero WC. Far-lateral disc herniations: the results of conservative management. J Spinal Disord. 1999;12:138-40. 6. Altman DG. Practical statistics for medical research. London: Chapman and Hall; 1991. 7. Shin BJ, Lee JC, Lee HH, Jang HD. Conservative treatment of lumbar disc herniation: a prospective study of disc herniation encroaching more than one-third of spinal canal. J Korean Soc Spine Surg. 2011;18:123-31. 8. Weber H. Lumbar disc herniation. A controlled, prospective
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447 pissn : 1226-2102, eissn : 2005-8918 Original Article J Korean Orthop Assoc 2017; 52: 442-447 https://doi.org/10.4055/jkoa.2017.52.5.442 www.jkoa.org 요추극외측추간판탈출증과후외측추간판탈출증의수술에대한상대위험도 : 후향적코호트연구 하대호 심대무 * 김태균 * 오성균 김진 원광대학교의과대학산본병원정형외과, * 원광대학교의과대학정형외과학교실, 원광의과학연구소 목적 : 코호트연구를통해요추후외측탈출증과극외측탈출증환자의수술에대한상대위험도를알아보고자하였다. 대상및방법 : 요추추간판탈출증으로진단된환자중일측방사통에대해경추간공하경막외차단술을시행받은총 295명의환자에대해후향적코호트연구를시행하였다. 극외측탈출증으로진단된 34명과후방혹은후외측탈출증으로진단된환자는 261명이었다. 이들의중앙추시기간은 23.9개월이었고, 평균연령은 55.7세, 남성은 131명, 여성은 164명이었다. 결과 : 추시중총 51명이수술을시행받았으며, 38명은후방혹은후외측추간판탈출증이었고 13명은극외측추간판탈출증이었다. 척추관내추간판탈출증에비해극외측탈출증이었던경우수술에대한상대위험도 (relative risk) 와 95% 신뢰구간 (95% confidence interval) 은 2.67 (1.59-4.48) 이었으며이러한관련성은통계적으로도유의하였다 (p=0.0002). 극외측추간판탈출증환자들의수술군과비수술군의최종추시방사통에대한평균시각통증등급 (visual analogue scale) 은 0.69, 1.50으로비수술군이유의하게높았고 (p=0.035), Korean-Oswestry Disability Questionnaire 는각각 11.7점, 9.6점유의한차이를보이지는않았다 (p=0.266). 결론 : 극외탈출증의경우척추관내탈출증에비해신경차단술후수술에대한상대적위험도가 2.67로높아보다적극적으로수술을고려해야한다. 색인단어 : 요추, 추간판절제술, 경막외신경차단술 접수일 2016 년 11 월 25 일수정일 2017 년 1 월 3 일게재확정일 2017 년 3 월 20 일책임저자오성균 15865, 군포시산본로 327, 원광대학교의과대학산본병원정형외과 TEL 031-390-2224, FAX 031-390-2223, E-mail niceo@hanmail.net * 본연구는 2017 년원광대학교연구비지원에의하여수행됨. 대한정형외과학회지 : 제 52 권제 5 호 2017 Copyright 2017 by The Korean Orthopaedic Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.