Original Article Discectomy for Herniated Lumbar Disc in Resource Limited Settings: Loupe or Microscope?

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1 Egyptian Journal of Neurosurgery Volume 30 / No. 4 / October - December Original Article Discectomy for Herniated Lumbar Disc in Resource Limited Settings: Loupe or Microscope? Salah M Hamada * and Ahmed H Abou-Zeid Department of Neurosurgery, Ain Shams University, Cairo, Egypt Received: 31 October 2015 Accepted: 30 Decmber 2015 Key words: Discectomy, Microdiscectomy, Loupe, Headlights 2015 Egyptian Journal of Neurosurgery. All rights reserved ABSTRACT Background: Loupes and microscopes are common magnification tools used during lumbar discectomy. Objective: In resource limited settings where microscopes are not readily available, we hypothesize that if properly used, magnifying loupes with headlights could offer comparable results to the microscope in relieving leg pain which is the primary goal of discectomy. Patients and Methods: Prospective cohort study was conducted on ninety-seven de novo single level lumbar disc prolapse patients with a predominance of radicular leg pain between January 2009 and September The microscope was used in twenty-nine patients (29.9%) and loupe with headlight in sixty-eight cases (70.1%). Pre-operative assessment included a thorough clinical examination with a focus on spine assessment. Surgical indications included failure of at least 6 weeks medical treatment, intractable pain or progressive neurological deficits. Same Surgical technique was used in all patients. Per-and post operative parameters recorded included: length of the incision, operative time, blood loss, the presence of a wound drain, length of hospital stay, leg and back pain before discharge and in follow up visits and complications. Pain severity was assessed using the visual analogue scale (VAS). Results: The baseline demographic, clinical, radiological characteristics and surgical technique were similar and comparable (p>0.05). The mean length of the incision was 2.1 cm for the microscope group and 2.8 cm for the loupes group (P value =0.0007). The loupe group had more bilateral muscle separation than the microscope group (P=0.011). There wasn t any statistically significant difference in both groups as regard the extent of bony work (p-value=0.09), duration of operation (p=0.85), blood loss (p=1), use of drain in post-operative period (p=0.16), complication rate and length of hospital stay (p=0.21). There wasn t any statistically significant difference in VAS score for leg pain (p=0.32) and low back pain (p=0.46). Radicular pain recurred in equal proportion in both groups (p=0.17). Twenty-five cases (86.2%) in the microscope and sixty-three cases (92.6%) in the loupe group had a 3 months post-operative VAS of zero (p=0.32). Conclusion: Operative microscope and loupes with headlights are both acceptable alternative tools in lumbar discectomy since both have similar and comparable outcome. In settings with limited access to microscopes, loupes with headlights are safe and effective tools for magnification and illumination in lumbar discectomy.. INTRODUCTION Lumbar discectomy and decompression relieves pressure on the nerve caused by the prolapsed disc resulting in improvement of symptoms and early return to function 1-5. Loupes and the microscopes are common magnification and illumination tools used in discectomy 1,6-8. In developed countries, microscopic discectomy 9 is the standard technique performed via small incision, limited muscle dissection and bone excision 10 with proven effectiveness over open macro discectomy 9,11. However, in resource limited settings, open lumbar discectomy with or without the use of loupes and headlights for illumination/magnification is not uncommon as only 70% of surgeons in a developed setting admitted using the microscope in one survey 12. *Corresponding Author: Salah Mostafa Hamada Department of Neurosurgery, Ain Shams University, Cairo, Egypt. salahhamada@gmail.com; Tel: To the best of our knowledge, only one paper in French and English Literature which is a non-concurrent cohort compares the loupes and the microscopes in lumbar discectomy with results in favour of the microscopes for offering better visualization, being more comfortable for the surgeon, and a much better teaching tool 13. Other authors have confirmed the facilitatory and visualization advantages of the microscope but argued that it does not improve the final results when compared to macro discectomy 8,14. PATIENTS AND METHODS Study Design: Prospective concurrent cohort study on ninetyseven patients having surgical intervention for a single level lumbar disc prolapse with a predominance of radicular leg pain. Our preference was to use the microscope ( gold standard ) 2 unless it was not available when we used loupes and headlights Egyptian Journal of Neurosurgery 299

2 (Intervention group). The microscope (Zeiss S88) was used in twenty-nine patients (29.9%) and loupe (Keeler 2.5X) with LED headlight in sixty-eight cases (70.1%). All the operations were undertaken between January 2009 and September Inclusion Criteria: The indication for surgery was failure of medical treatment for at least six weeks (XTable 1X) except for six patients who had earlier surgery (in less than six weeks) due to intractable pain or progressive neurological deficits. Two were operated at one and 4 weeks due to progressive neurological deficits and 4 patients operated on at 4 weeks due to intractable pain. Exclusion Criteria: We excluded patients with multilevel, or recurrent disc prolapse, lumbar canal stenosis and when there was need for lumbar fusion (XTable 1X). Table 1: Inclusion and Exclusion Criteria Inclusion Criteria Single level disc prolapse Failed medical treatment No previous lumbar surgery Exclusion Criteria Multiple level disc prolapse Previous lumbar surgery Bony or ligamentous canal stenosis When there is need for lumbar fusion Pre-operative assessment: All patients underwent a thorough clinical examination with a focus on spine assessment. The sociodemographic data and antecedent medical history were also recorded. The characteristics of the radicular pain (duration, distribution) were recorded with the severity assessed using the visual Analogue Scale (VAS) (15). Surgical technique We operated on all patients under general anaesthesia with endotracheal intubation. All patients received prophylactic antibiotics with the induction of anaesthesia in addition to two postoperative doses. Patients were positioned prone and semi-flexed using bolsters with careful protection of pressure areas. Alcoholic povidone-iodine was used for skin cleansing in all cases and left on patients skin for at least 4 minutes. We marked the incision site using the image intensifier when available and utilized a midline incision with muscle separation. We used Caspar lumbar microdiscectomy retractor in all cases. We used fluoroscopy for the majority of cases in the loupes group and all the patients in the microscope group and in these cases we tailored the incision to the direction of disc fragment migration, for example, a more cranially placed incisions in cranially migrating disc fragments. Per-operative parameters recorded included: length of the incision, operative time, blood loss, the presence of a wound drain, and complications of surgery. Postoperative care and assessment Patients were mobilized on the same day a few hours after surgery. Routine painkillers were provided to patients postoperatively including Paracetamol and non-steroidal anti-inflammatory drugs. Clear instructions were provided to the patients including wound care, lifting, sitting and posture advice. Wounds were inspected a week following the operation, then patients were offered a follow up appointment at three and eight weeks. Patients were asked to record their back and leg pain score on the visual analogue score (VAS) before discharge and in their follow up visit. Other collected data included length of stay and postoperative complications. Statistical Methodology Chi-square tests and analyses of variance were used to compare the baseline characteristics of the cases between the two treatment groups. Age, pain severity, duration of symptoms, were analysed as a discrete variable while sex, disc level, location and size were categorized. The main outcome measure was pain intensity (sciatica) at 3 months after surgery. Secondary outcome measures were: length of the incision, operative time, blood loss, the presence of a wound drain, complications of surgery and length of hospital stay. Analysis was done using STATA/MP version 13.0 RESULTS Ninety-seven patients underwent a single level lumbar microdiscectomy procedure for predominantly lumbar radicular symptoms by the main author in the five-year study period. Sixty-eight patients (70.1%) were operated using loupes and headlights and 29.9% (N=29) using the surgical microscope. Mean age ± 300 Egyptian Journal of Neurosurgery

3 Standard Deviation (SD) was 39.5 ± 9.4 years (range 22-64). There wasn t any statistically significant difference in the age (p-value=0.56) nor sex (p-value=0.48) for both treatment groups making them comparable as regard these demographic parameters (Table 2). There wasn t any statistically significant difference in the baseline clinical features for both treatment groups making them comparable (Table 3). All the patients had low back pain and radicular pain. For both groups, the mean back pain VAS was 5.0 (pvalue=0.97) and leg pain severity score was 8.3 (pvalue=0.82). The median duration preoperative symptom was 5 months for the microscope group and 5.5 months for loupe group (p-value= 0.9). Most of the operated levels in both groups were L5/S1 and L4/5.Using the MSU Classification (16) for the grading of herniated disc size, there wasn t any statistically significant difference for both treatment (pvalue=0.63) likewise for disc location (p-value=0.56). There wasn t also any statistically significant difference in the laterality of the disc (disc side) (p-value=0.17) and degree of disc generation using Pfirrmann s grading (17) (p=0.88), thus, both groups were comparable radiologically (Table 4). Table 2: Patients Baseline Demographic Data Variable AGE/Years Mean (±SD) 39.49± ± ± * SEX Male (75.9) 46 (67.65) 0.48** Female 29 7 (24.1) 22 (32.35) * t-test for equal variances **Pearson chi2 Table 3: Patients Baseline Clinical Data Variable Low Back Pain Severity 5.0± ± * Mean VAS ±SD Radicular Pain Severity 8.3± ± ± * Mean VAS ±SD Straight Leg Raising Yes (SRL<60)= n (%) 23 (79.31) 63 (92.65) 0.06 No= n (%) 6 (20.67) 5 (7.35) Duration of symptoms /months Median (P25, P75) 5 (3 9) 5 (3 9) 5.5 (3 9) 0.90** * Two-sample t test with equal variances Fisher s Exact Test **Two-sample Wilcoxon rank-sum (Mann-Whitney) test Egyptian Journal of Neurosurgery 301

4 Table 4: Patients Baseline Radiological Data Variable Disc Level L5-S1 15 (51.7) 33 (48.5) L4-L5 10 (34.5) 33 (48.5) L3-L4 + L2-L3+ L1-L2 4 (13.8) 2 (2.9) Disc Size I 4 (13.8) 5 (7.4) II 17 (58.6) 41 (60.3) 0.63 III 8 (27.6) 22 (32.4) Disc Location A 2 (6.9) 2 (2.9) AB 13 (44.8) 40 (58.8) ABC 1 (3.5) 3 (4.4) 0.56 B 10 (34.5) 20 (29.4) BC 2 (6.9) 2 (2.9) C 1 (3.5) 1 (1.5) Fisher s Exact Test OUTCOME With regard to surgical technique, the mean length of the incision was 2.1 cm for the microscope group and 2.8 cm for the loupes group. Although the difference was highly statistically significant (P value =0.0007), the mean difference was only 0.7 cm [95% CI ( cm)]. Although, more patients of the loupe group had unilateral muscle separation, they also underwent more bilateral muscle separation than the microscope group. (P-value=0.011) There wasn t any statistically significant difference in both groups as regard the extent of bony work (pvalue=0.09), technique of discectomy (p-value=0.18), duration of operation (p=0.85), blood loss (p=1), use of drain in post-operative period (p=0.16), complication rate and length of hospital stay (p=0.21) (XTable X5) Table 5: Surgical Technique and Operative Outcome Variable Length of Skin Incision (cm): Mean±SD 2.1± ± * Muscle Separation Unilateral (36.5) 47 (63.5) Bilateral 23 2 (8.7) 21 (91.3) Bony Work Fenestration (33.8) 53 (66.3) 0.09 Laminectomy 17 2 (11.8) 15 (88.2) Technique of Discectomy Fragmentectomy 2 0 (0) 2 (100) Classical Discectomy (29.0) 66 (71) 0.18 Bony Decompression without discectomy 2 2 (100) 0 (0) Duration of operation (minutes): Mean ±SD 84.3± ± * Volume of blood loss (cm) >100cc 0 (0) 1 (100) cc 29 (30.2) 67 (69.8) Use of Drain Yes 1 (9.1) 10 (90.9) No 28 (32.9) 57 (67.1) 0.16 Unintended Durotomy=Yes n (%) 5 2 (40) 3(60) 0.63 CSF Leak=Yes n (%) 2 0 (0) 2(100) 1 Infection (Superficial) =Yes n (%) 3 0(0) 3(100).56 Length of Hospital Stay/days: Mean±SD 1.7± ± * Fisher s Exact Test * t-test for equal variances **Pearson chi2 Two-sample Wilcoxon rank-sum (Mann-Whitney) test 302 Egyptian Journal of Neurosurgery

5 Table 6: Follow up and Outcome of Pain Variable n Follow Up duration/months: 0.19 Median (P25, P75) 5 (4 12) 5 (3 6) Immediate Post-op Severity of radicular pain: Median (P25, P75) 0 (0 1) 0 (0 0) 0.62 (min max) (0 5) (0 7) Severity of radicular pain at 3 months: 0.32 Median (P25, P75) 0 (0 0) 0 (0 0) (min max) (0 8) (0 7) Change in Severity of radicular pain (VAS pre-op- VAS at 3 months ) Median (P25, P75) 8 (7 9) 8 (7 9) 0.92 (min max) (1 10) (1 10) Severity of low back pain at 3 months: 0.46 Median (P25, P75) 2 (0 2) 1 (0 2) (min max) (0 6) (0 6) Recurrence of sciatica=yes n(%) 13 6 (46.2) 7 (53.8) 0.17 Fisher s Exact Test * t-test for equal variances Two-sample Wilcoxon rank-sum (Mann-Whitney) test The median follow up period was similar in both groups (p=0.19). There wasn t any statistically significant difference in VAS score for leg pain (p=0.32) and low back pain (p=0.46). Radicular pain recurred in equal proportion in both groups (p=0.17) (XTable X6). Median leg pain dropped from 9 to 0 [25 cases (86.2%) with 3 months post-op VAS=0] and from 8 to 0 [63 cases (92.6%) with 3 months post-op VAS=0] on the visual analogue score for the microscope and loupes groups respectively at three months following surgery. DISCUSSION In resource limited settings where microscopes are not readily available, we hypothesize that if properly used, magnifying loupes with headlights for illumination and magnification could offer comparable results to the microscope in relieving leg pain which is the primary goal of discectomy. We advocate for the use of the loupe and headlight (LAH) in resource limited settings on the grounds of easy access to and unsophisticated visualization of the operating field, portability avoiding the cumbersomeness of complicated equipment, cost-effectiveness because of no utilization fee and operator freedom and comfort which may decrease operating time. Less magnification does not mean less quality as there is no documented minimum threshold magnification for optimal safe discectomy and that of the LAH ought to be enough for effective and safe discectomy. Microscopic discectomy is the standard treatment 10,18 for herniated lumbar disc with proven effectiveness and safety. However loupes and headlights are routinely used when the microscope is unavailable and open discectomy is not uncommon especially in developing countries. In the 2009 Canadian national survey by Cenic and Kachur regarding the tool used by neurosurgeons for lumbar disc surgery; results revealed that 70% of responding surgeons routinely used the microscope and just less than 20% used loupes for magnification during lumbar disc surgery 12. To the best of our knowledge, there is only one paper in the French and English literature comparing lumbar discectomy utilizing the loupes and the operating microscope with results in favour of the microscope with significantly better outcome, less complications and earlier return to function but non-significant difference in patient satisfaction and visual analogue score 13. In resource limited settings where microscopes are not readily available for the aforementioned reasons, magnifying loupes with headlights for illumination and magnification offers comparable results to microdiscectomy and could be a more effective and safer alternative than open (naked eye) macro discectomy since the microscope has been proven to be superior to the latter 8,14. The baseline sociodemographic, clinical and radiological characteristics were similar in both treatment groups limiting selection bias and rendering them comparable (XTable 2X, 3 & 4) Expertise bias is a major problem with the assessment of tools in surgery 16. This wasn t a major confounder in our study since both tools (loupes and microscope) were used by the same surgeons. Although surgical treatment itself is variable and hard to standardize, the same procedure of discectomy was done in all patients and like Kumar et al 13, only patients requiring a single-level discectomy or decompression were included to reduce selection bias. Egyptian Journal of Neurosurgery 303

6 Regarding the surgical technique, although the mean length of the incision was statistically longer for loupes (2.8cm) than for the microscope group (2.1cm) (P=0.0007), the standardized mean difference was only 0.7 cm with no repercussion on the post operative low back pain at 3 months follow-up (Median VAS pain score (p50)=2 for microscope and 1 for loupe and p- value = 0.46). Likewise, even though there is a significant difference in the extent of muscle separation, more patients of the loupe group had bilateral muscle separation as well as unilateral muscle separation than the microscope group (p-value=0.011). This difference could be accounted for as some patients in this group were operated on without fluoroscopy so we had to extend the wound and increase muscle separation to ascertain the correct surgical level. None-the-less, in the majority of cases, we used fluoroscopy and tailored the incision site according to the direction of the prolapsed fragment, which we think helped in reducing the incision length and avoiding excessive un-necessary muscle dissection or wound extension after initial exposure. In our study, we found no statistically significant difference between both groups in terms of extent of bony work, technique of discectomy, operative time, blood loss, length of hospital stay [Table 5]. Kumar et al 13 found a longer operative time with the microscope and related it to be due to time needed to drape the microscope; in our study we found the converse. Our mean length of hospital stay was longer for the microscope group results similarto those ofkumar et al 13. Regarding complications, none of the microscope group and only one patient in the loupe group had blood loss of more than 200 cc. We left a wound drain in one patient of the microscope group (3.4%) and ten patients of the loupe group (14.7%). Unintended durotomy occurred in two patients of the microscope group (6.9%) without any postoperative CSF leak or requiring any further intervention and in three patients of the loupe group (4.4%). Two patients had postoperative CSF leak, which settled without further intervention in one patient and resulted prolonged hospital stay (10 days) in the second patient and re-intervention later for repair of a pseudomeningocele. We had three cases of superficial wound infection in the loupe group (4.4%) and no infections in the microscope group results similar to those of Kumar et al 13. Although the use of headlamp/loupes or the operative microscope has been described to be associated with bacterial shedding, no significant difference was noted using both tools, suggesting that infection risk should not come into play when choosing techniques of illumination/magnification 19. However, 304 proper techniques of cleaning, storage, and draping should be used to minimize their contribution to potential postoperative infection. There wasn t any statistically significant difference in the severity of radicular pain in the immediate postoperative period (p=0.62) and at 3 months follow-up (p=0.32). Unlike Kumar et al 13 who found a slight better improvement in radicular pain for the microscope group, ours were indifferent. Likewise the outcome of low back pain was similar in both groups at three months follow-up (p=0.46) although the interpretation of such results should be done with caution because of the complex etiopathogenesis of low back pain in herniated disc. 20,21 Besides the outcome of low back pain is less impressive in the early post operative period while resolution of radicular pain is almost always immediate hence the latter and not the former was our primary outcome. We re-operated on four patients during the study period. One patient (3.4%) in the microscope group and three patients in the loupes group (4.4%) had recurrence necessitating reoperation in 1 week, 1 week, 3 and 24 months respectively in addition to the patient who needed repair of pseudomeningocele. One patient in the loupes group had reoperation in another centre 12 weeks following the initial operation for recurrent symptoms. Cenic and Kachur reported in their survey that 68% of responders admitted they removed as much disc material as they could from within the disc space 12 whilst the minority of the responders removed only the herniated part. Faulhauer and Manicke reported less recurrences and instability problems with fragment removal compared to aggressive discectomy 22 while Fakouri et al 23, concluded that microscopic sequestrectomy is more successful with lesser operating time, fewer intraoperative complications, and lesser reherniation rate compared with conventional microdiscectomy. Our inclination was more towards aggressive discectomy in many cases, which might be the reason behind our relatively lengthy operative time. Limitations of our study: Unlike Kumar et al 13, we didn t assess the functional outcome scores,quality of life and overall patient satisfaction, which we think would have provided more useful overall information of postoperative status. Strengths of our study: This will be the first prospective concurrent cohort study comparing the loupe and microscope for lumbar discectomy involving a homogeneous sample and done by a neurosurgeon at the asymptotic stage using both tools. Unlike the study of Kumar et al 13 in which the baseline characteristics is questionable (no statistical evidence of comparability of their two groups) and data could be biased (recall and interviewer bias) as it was retrospectively collected via phone calls, our study Egyptian Journal of Neurosurgery

7 groups were demographically, clinically and radiologically similar and comparable (p>0.05). Data collection was prolective and less liable to systematic error. CONCLUSION Operative microscope and loupes with headlights are both acceptable alternative tools in lumbar microdiscectomy since both have similar and comparable outcome. In settings with limited access to microscopes and other minimally invasive tools such as the endoscope with proven safety and effectiveness over macrodisectomy, loupes with headlights are safe and effective tools for magnification and illumination in lumbar discectomy. Declaration: The authors have no personal, financial or institutional interest in any of the materials described in this article Acknowledgment: The authors would like to thank Dr Ignatius N Esene for his help with statistics REFERENCES 1. Abou-Zeid A, Palmer J, Gnanalingham K. Day case lumbar discectomy--viable option in the UK? Br J Neurosurg 28:320-3, Pearson AM, Blood EA, Frymoyer JW, Herkowitz H, Abdu WA, Woodward R, et al. SPORT lumbar intervertebral disk herniation and back pain: does treatment, location, or morphology matter? Spine 15;33:428-35, Peul WC, van den Hout WB, Brand R, Thomeer RT, Koes BW. Prolonged conservative care versus early surgery in patients with sciatica caused by lumbar disc herniation: two year results of a randomised controlled trial. BMJ 14; 336:1355-8, Rothoerl RD, Woertgen C, Brawanski A. When should conservative treatment for lumbar disc herniation be ceased and surgery considered? Neurosurg Rev 25:162-5, Schoenfeld AJ, Weiner BK. Treatment of lumbar disc herniation: Evidence-based practice. Int J Gen Med 3: Koebbe CJ, Maroon JC, Abla A, El-Kadi H, Bost J. Lumbar microdiscectomy: a historical perspective and current technical considerations. Neurosurg Focus 15; 13:E4, Newsome RJ, May S, Chiverton N, Cole AA. A prospective, randomised trial of immediate exercise following lumbar microdiscectomy: a preliminary study. Physiotherapy 95: 273-9, Tureyen K. One-level one-sided lumbar disc surgery with and without microscopic assistance: 1- year outcome in 114 consecutive patients. J Neurosurg 99: S247-50, Rasouli MR, Rahimi-Movaghar V, Shokraneh F, Moradi-Lakeh M, Chou R. Minimally invasive discectomy versus microdiscectomy/open discectomy for symptomatic lumbar disc herniation. Cochrane Database Syst Rev 9:CD Riesenburger RI, David CA. Lumbar microdiscectomy and microendoscopic discectomy. Minim Invasive Ther Allied Technol 15: Schick U, Dohnert J, Richter A, Konig A, Vitzthum HE. Microendoscopic lumbar discectomy versus open surgery: an intraoperative EMG study. Eur Spine J 11:20-6, Cenic A, Kachur E. Lumbar discectomy: a national survey of neurosurgeons and literature review. Can J Neurol Sci 36: , Kumar SS, Mourkus H, Farrar G, Yellu S, Bommireddy R. Magnifying loupes versus microscope for microdiscectomy and microdecompression. J Spinal Disord Tech 25: E235-39, Lagarrigue J, Chaynes P. [Comparative study of disk surgery with or without microscopy. A prospective study of 80 cases]. Neurochirurgie 40: Bijur PE, Silver W, Gallagher EJ. Reliability of the visual analog scale for measurement of acute pain. Acad Emerg Med 8:1153-7, Bhandari M, Joensson A. Clinical Research for Surgeons. Thieme; PP Pfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine (Phila Pa 1976) 1; 26: Sep Apostolides PJ, Jacobowitz R, Sonntag VK. Lumbar discectomy microdiscectomy: "the gold standard". Clin Neurosurg 43: Weiner BK, Kilgore WB. Bacterial shedding in common spine surgical procedures: headlamp/loupes and the operative microscope. Spine 15; 32:918-20, Truumees E. Discogenic Low Back Pain. In: Vincent J.Devlin, editor. Spine Secrets Plus. St Louis, Missouri: Elsevier Mosby; pp Esene IN, Meher A, Elzoghby MA, El-Bahy K, Kotb A, El-Hakim A. Diagnostic performance of the medial hamstring reflex in L5 radiculopathy. Surg Neurol Int 3:104, Faulhauer K, Manicke C. Fragment excision versus conventional disc removal in the microsurgical treatment of herniated lumbar disc. Acta Neurochir (Wien) 133:107-11,1995 Egyptian Journal of Neurosurgery 305

8 23. Fakouri B, Patel V, Bayley E, Srinivas S. Lumbar microdiscectomy versus sequesterectomy/free fragmentectomy: a long-term (>2 y) retrospective study of the clinical outcome. J Spinal Disord Tech 24:6-10, Egyptian Journal of Neurosurgery