Abstract

Original Article Journal of Bone and Joint Diseases| Sep - Dec 2019 | 34(3): 3-7

© 2019 by Journal of Bone and Joint Diseases | Available on www.jbjdonline.com | DOI 10.13107/jbjd.2019.v34i03.002�is is an Open Access article distributed under the terms of the Creative Commons A�ribution Non-Commercial License (h�p:// creativecommons.org/licenses/by-nc/3.0) which

permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

IntroductionLow backpain affects around 70- 80% of population at some point in their lifetime. Lumbar disc disease has been a major burden both medically and economically on affected population[1]. �ose who fail to respond to conservative management o�en need open or minimally invasive surgery for the management of their intractable radicular symptoms[2]. It was Mixter and Barr who �rst introduced extensive laminectomy as a technique for treatment of lumbar disc herniations back in 1934[3]. However bigger incision, greater so� tissue stripping, more loss of blood and long term surgery related back pain and denervation atrophy of muscles of back has led to low functional and patient satisfaction rates paving way for minimally invasive techniques[4,5]. Hemilaminectomy became popular as a procedure for patients with unilateral symptoms. It was Love who �rst introduced the interlaminar fenestration technique for the removal of herniated lumbar disc[6] As compared to laminectomy disc removal by interlaminar fenestration

technique has various advantages such as lower postoperative back ache, early resumption of work, early mobilization post discectomy[7]. And these are due to lesser so� tissue stripping, maintained spinal stability and lack of membrane formation as seen in laminectomy [8].�e purpose of this study is to evaluate the functional and neurological outcome in patients operated for lumbar disc disease by interlaminar fenestration technique.

Materials and methodsWe conducted a prospective study between January 2011 and December 2013 on 36 patients with lumbar disc prolapse who underwent lumbar discectomy by interlaminar fenestration technique. We included those patients who had severe radicular pain and had no improvement by conservative treatment, those who showed signi�cant and/or progressive neurological de�cit and those with bowel and bladder symptoms. �e patients with disc prolapse at multiple levels, disc prolapse other than lumbar level, discitis, spinal canal

¹Department of Orthopaedic Surgery, J.N. Medical College, A.M.U, Aligarh, 202002.

Address of Correspondence:Dr. Ziaul Hoda Shaan,Department of Orthopaedic Surgery, JNMCH AMU, Aligarh,E-mail: shaan.hoda007@gmail.com

Dr. Sohail Ahmad Dr. Ziaul Hoda Shaan

Prolapsed intervertebral disc is one of the most common crippling back disorder and affects around 4-6% of population who present with clinically signi�cant sciatica. As a surgical procedure fenestration discectomy is less time consuming, blood loss is less, with lesser post surgical complications and stability compromise of spine is lesser when compared to laminectomy. �is study was conducted in order to know the functional outcome in terms of pain relief and return to work in patients treated by interlaminar fenestration technique for lumbar disc prolapse.Materials and Methods: �irty six patients who presented with signs and symptoms of prolapsed disc and had no relief with conservative treatment were operated by interlaminar fenestration technique. Modi�ed McNabs’s criteria and ‘Back Pain Functional Score (BPFS)’ given by Stratford et al was used to evaluate the Functional outcome. Pre and post operative visual analogue scale (VAS) score were calculated and compared.Results: �e ‘Back Pain Functional Score’ improved from a preoperative value of 30.8±4.1 to 46.1±4.6(p value <0.0001) Based on modi�ed Macnab’s criteria 29 (80.6%) patients had good, 05 (13.8%) patients had fair and 02(5.6%) patients had poor outcome. Preoperative mean VAS was 7.8±1.3 which improved to 3.3±0.95 postoperatively (p value < 0.0001).Conclusion: In the peripheral institutions, disc excision by interlaminar fenestration is a reasonable method to surgically treat the indicated cases of prolapsed disc with good functional outcome and lesser postoperative morbidity.Keywords: Sciatica; prolapsed intervertebral disc; Fenestration Discectomy.

Sohail Ahmad¹, Ziaul Hoda Shaan¹, Latif Z. Jilani¹, Mohd. Faizan¹, Naiyer Asif¹, Mazhar Abbas¹

Treatment of lumbar disc prolapse by Interlaminar Fenestration Technique

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Dr. Latif Z. Jilani Dr. Mohd. Faizan Dr. Naiyer Asif Dr. Mazhar Abbas

stenosis and prior spinal surgery were excluded from the study.A�er proper history and clinical examination of all patients magnetic resonance imaging (MRI) of lumbosacral spine with screening of whole spine was done. A�er clinico-radiological con�rmation of the diagnosis the patients were planned for surgery. Patient’s daily routine work preoperatively was recorded for employment status. Li�ing or pulling- pushing of up to 8-10 kilograms of weight, standing or walking for 2 hours daily in a work hour duration of 8 hours per day, post retirement and household work were de�ned as light or sedentary work. Pulling, pushing or li�ing 30-40 kg of weight or more and regular li�ing of weight of 20 kg or more during work hour duration of 8 hours daily was de�ned as strenuous activity.A�er general anaesthesia all patients were operated in prone position with bolsters under both shoulder and anterior superior iliac spine with the hip and knee �exed to 90⁰. A 2-3 inches midline skin incision was given a�er con�rming the level in �uoroscope. �e offending disc was removed by standard interlaminar fenestration technique where as far as possible access was made through ligamentum �avum. In some cases we had to remove inferior third of upper lamina or

superior third of lower lamina for adequate removal of sequestrated disc (�gure1 and 2).Ner ve roots were decompressed in all cases. Bipolar cautery was used to achieve hemostasis. In cases of accidental dural tear, the ones which were amenable to repair were sutured by nonabsorbable sutures, while the ones that were out of access were closed with �brin glue. Epidural fat was laid over the nerve root in order to minimize the chances nerve root compression due to adhesion formation post operatively. All the surgeries were done by single surgeon. Patients were mobilized from next day of surgery. Forward bending or li�ing heavy objects was prohibited for �rst 6 weeks. Spinal extension exercises were

Ahmad S et al www.jbjdonline.com

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Figure 1: a) Shows the positioning of the patient in knee chest position; b) Shows the skin incision midline of about 2-3 inches; c) Level con�rmed under �uoroscope before incision; d)schematic diagram showing spinal canal with nerve root and sac; e & f) Show whitish and shiny disc with retracted nerve root and sac.

Figure 2: a) and c) shows the saggital and transverse magnetic resonance image of the prolapsed disc at L5-S1 level; b) Shows the disc removed a�er fenestration approach.

Number of

pa�entsPercentage

Hip 0 0%

Knee 8 22.20%

Ankle 16 33.30%

EHL 19 52.70%

Sensory deficits 25 69.40%

Posi�ve Straight leg raise test 36 100%

Posi�ve Lasegue test 36 100%

Scia�c list 14 38.80%

Knee 4 11.10%

Ankle 10 27.70%

Loss of lumbar lordosis 30 83.30%

Bowel bladder involvment 2 5.50%

Table 1: Shows preopera�ve examina�on findings and distribu�on among pa�ents.

Diminished to absent Deep

Tendon Reflex

Preopera�ve examina�on findings

Power deficits

Number of

pa�ents

Percentage

of pa�ents17 47.22%

3/5 3 8.3%

2/5 2 5.5%3/5 3 8.3%

2/5 2 5.5%

1/5 1 2.7%

3/5 3 8.3%

2/5 2 5.5%

3/5 7 19.4%

2/5 3 8.3%

3/5 1 2.7%

2/5 2 5.5%

Evertors 3/5 1 2.7%

3/5 2 5.5%

2/5 1 2.7%

3/5 3 8.3%

2/5 6 16.6%

Ankle extensor group

Knee extensors

EHL

Table 2: shows distribu�on of pa�ents according to Motor weakness

Evertors

Knee extensor

EHL

Right side

Motor deficits

Nil

Le� side

Ankle extensor group

started from 3 weeks post surgery. Patients were followed up at 3 weeks, 6 weeks, 3 months and 6 months on OPD basis with the �nal follow up at 1 year.Modi�ed MacNabs’s criteria were used to evaluate the result of surgery. Preoperative and post operative analyses of patient’s symptoms were done using ‘Back Pain Functional scale’ given by Stratford et al9. Pre and post operative visual analogue scale (VAS) score were calculated and compared. Statistical analysis was performed using Paired student’s t-test.

Results We included 36 patients out of which 23 were males and 13 were females. �e average age of patients included in the study was 35.5 years (range 25-55 years). Nine(25%) out of 36 patients were involved in strenuous activities while other were involved in light duty. Eight (22.2%) patients had history of li�ing heavy object prior to start of symptoms while the others had insidious onset. Nineteen patients had le� sided symptoms, 17 had right sided and none had bilateral symptoms. In patients with insidious onset of symptoms the radicular pain and low back ache were from an average of 3.2 and 8.5 months. Paraesthesia was present in 10(27.7%) patients. Dermatomal numbness was present in 12(33.3%) patients. Straight leg raise test and Lasegue test was positive in all the patients (range 35⁰ to 60⁰). Detailed motor and sensory examination was done for all patients. (Table 1 and 2)Commonest level of involvement was L5-S1 in 21(58.3%) followed by L4-L5 in remaining patients. Central or posterocentral position of the disc was most common 28 (77.7%). Disc protrusion was present in 15(41.6%) patients, extrusion in 18(50%) and sequestration in 3(8.3%) patients. Average surgery time was 82 minutes (range 50-120 minutes). Mean duration of hospital stay was 5 days (range 4-7 days). Average amount of blood loss during the surgery was 130 ml

(120- 275 ml).Seventeen (47.2%) patients returned to work in less than two months a�er surgery. Twenty eight (77.8%) patients returned to their original work while 8 (22.2%) had to change their nature of work. �irty two patients (88.9%) had relief in their radiculopathy while 30 patients (83.3%) had relief in their backache symptoms. Out of nineteen patients who had motor weakness, 16 (88.9%) recovered fully while 2 had partial recovery at the last follow up. One patient who did not show motor recovery had severe cauda equina syndrome with urinary incontinence. Out of two patients with bladder involvement one recovered fully at 6 weeks follow up. Two patients had inadvertent dural tear. One tear was repaired by non absorbable suture while the other one had to be sealed by �brin glue. Five patients developed urinary retention in post operative period who had to be catheterised for one day and were normal a�er catheter removal. We did not encounter any complications with wound healing, any iatrogenic motor weakness in post operative period. No case of deep vein thrombosis or pulmonary embolism were seen.Based on modi�ed MacNab’s criteria 29(80.6%) patients had good, 05(13.8%) had fair and 02(5.6%) had poor outcome. Preoperative mean VAS was 7.8±1.3 which improved signi�cantly to 3.3±0.95 postoperatively (t value-15.355539, degree of freedom-35,p value-0.0001)(Table-3).Preoperative and operative ‘Back pain functional score’ given by Stratford et al was recorded for all patients and compared. Paired t test was used to �nd the level of signi�cance and the improvement was statistically signi�cant. (p value <0.005, t value- -14.4, degree of freedom- 35) (Table-3).

Discussion Intervertebral disc disease constitutes 5-10% of all patients of low back ache and is a major cause of sciatic radiculopathy. Once the spinal canal is already compromised as a result of degenerative changes even a small disc prolapse can cause signi�cant morbidity in the form of nerve root compression and cauda equina syndrome. Wide laminectomy and excision of the offending disc has been the traditional way of treatment of the prolapsed intervertebral disc disease. With time the treatment modalities have evolved and disc surgeries are being done on day care basis, but these need long learning curve and dedicated surgeons. Inter-laminar fenestration approach to remove the offending disc was for the �rst time introduced by Love [10]. William further re�ned the interlaminar fenestration by using operating microscope for visualizing nerve roots, thecal sac and other structures within the spinal canal like the prolapsed disc[11]. Previous studies have shown increased morbidity due to wide laminectomy as compared to less invasive interlaminar fenestration technique[12].

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Score systemPreopera�ve

value

Post opera�ve

value

p- value (paired t-

test)

Visual analogue scale 7.8±1.3 3.3±0.95 <0.0001

Back pain func�onal scale (by

Stra�ord et al)30.8±4.1 46.1±4.6 <0.0001

Table 3: Sta�s�cal analysis of preopera�ve and post opera�ve func�onal outcome.

Previous studies

Good Fair poor

Aslam M. et al (2015) 75% 20% 5%

Sangwan SS et al (2006) 88.4% 7.6% 3.8%

P.S. Chakrabarty(2015) 96% 4% 0%

Manohara B et al.(2006) 90% 6.2% 3.8%Nahar et al.(2013) 80.42% 17.2% 2.71%

Garg et al. (2001) 86% 12% 2%

Wankhade U.G. et al.(2016) 84% 16% 0%

Func�onal outcome as per Mac Nab’s

Criteria

Table 4: Shows various published func�onal outcome a�er interlaminar fenestra�on .

By performing limited disc excision through the interlaminar fenestration technique the results we obtained lends support to this technique being simpler, easy to perform, safe, reliable and efficacious in selected patients of lumbar disc prolapse. In our study as per MacNab’s criteria good outcome was seen in 29 (80.6%), fair in05(13.8%) and poor in 02(5.6%) patients. �is functional result was similar to previous published papers [ 8,12,14,15,17].(Table -4)Seventeen (47.2%) patients returned to work in less than two months a�er surgery while 28 (77.8%) patients returned to their original work at last follow up with 8 (22.2%) changing their nature of work. �e percentage of patients returning to their original activity following disc removal by interlaminar fenestration technique ranges from 66.67% to 90%. [8,12,14,16,17]CompletePain relief a�er interlaminar fenestration discectomy has been quoted to be in the range of 64- 92% [12,15,17,18]. We also had 89.9% patients who had complete relief in radiculopathy symptoms and 83.3% patient who had complete relief in backache. �e duration and severity of preoperative symptoms has been proven to be signi�cantly related to the functional outcome as more chronic and severe the nerve root lesions lesser will be the chances of be�er functional outcome[19]. One of our patient had poor outcome as he had canal diameter of 4 millimetres and had cauda equina syndrome in form of bladder incontinence from 8.5 months. Studies comparing interlaminar fenestrat ion w ith

laminectomy have proven the bene�ts of the former in the form of decreased blood loss, lesser operative time, rapid recovery, no to minimal instability, no post operative complications of adhesions and easier rehabilitation [8,20]. Interlaminar fenestrat ion has the advantage over microdiscectomy in terms of lateral recess stenosis which can be dealt easily by the former. Here a surgeon can deal with a tight nerve root even a�er discectomy by foraminotomy or cu�ing one third of upper and lower lamina of the superior and inferior vertebra respectively[12]. Microdiscectomy needs long learning curve, proper instruments, more expertise. Interlaminar fenestration certainly requires greater exposure in comparision to microdiscectomy although so� tissue and paraspinal muscle fall back with good closure.Limitations of our study is the lack of long term follow up, we have not compared it with microdiscetomy technique which is less invasive and more re�ned technique. We have not taken into consideration the psycho-social aspect of lumbar disc disease.

ConclusionInterlaminar fenestration discectomy is a promising method of surgical treatment of prolapse disc disease of lumbar region. �e procedure is simple and easy, does not require costly instruments and training, and can be performed by new and average surgeon at any peripheral institution.

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1. Eguchi Y, Oikawa Y, Suzuki M et al: Diffusion tensor imaging of radiculopathy in patients with lumbar disc herniation: Preliminary results. Bone Joint J, 2016; 98-b(3): 387–94

2. Rasouli MR, Rahimi-Movaghar V, Shokraneh F et al: M i n i m a l l y i n v a s i v e d i s c e c t o m y v e r s u s microdiscectomy/open discectomy for symptomatic lumbar disc herniation. Cochrane Database Syst Rev, 2014; 9: Cd010328

3. Mixter WJ, Barr JS. Rupture of intervertebral discs with involvement of spinal canal. New Eng J Med. 1934; 211: 210-14.

4. Suwa H, Hanakita J, Ohshita N et al: Postoperative changes in paraspinal muscle thickness after various lumbar back surgery procedures. Neurol Med Chir (Tokyo), 2000; 40(3): 151–54; discussion 154–55

5. Skolasky RL, Wegener ST, Maggard AM, Riley LH III: The impact of reduc¬tion of pain after lumbar spine surgery: The relationship between changes in pain and physical function and disability. Spine, 2014; 39(17): 1426–32

6. Love JG. Root pain resulting from intraspinal protrusion of

vertebraldiscs: diagnosis and treatment. J Bone Joint Surg.1939; 19: 776-80.

7. Mishra SK, Mohapatra NC, Pradhan NK, Mohapatra MK. Lumbar disc excision. Comparative study of laminectomy and inter-laminar fenesration. Ind J Orthop. 1998; 33(3): 153-55.

8. Garg M, Kumar S. Interlaminar discectomy and selective foraminotomy in lumbar disc herniation. J OrthopSurg (HongKong). 2001 Dec 9 2):15-18.

9. Stratford PW Binkley JM et al. Development and initial validation of the Back Pain Functional Scale. Spine. 2000; 25: 2095-2102

10. Love JG. Root pain resulting from intraspinal protrusion of vertebral discs: diagnosis and treatment. J Bone Joint Surg.1939; 19: 776-80.

11. Williams RW. Micro lumbar disectomy; a conservative surgicalapproach to the virgin herniated lumbar disc. Spine. 1978; 3:17582.

12. Sangwan SS, Kundu ZS, Singh R, Kamboj P, Siwach RC, Aggarwal P. Lumbar disc excision through fenestration. Ind J Orthop. 2006;40(2):86-89.

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Con�ict of Interest: Nil Source of Support: None

How to Cite this ArticleAhmad S, Shaan Z H, Jilani L Z, Faizan M, Asif N, Abbas M Treatment of | lumbar disc prolapse by Interlaminar Fenestration Technique. Journal of | Bone and Joint Diseases Sep-Dec 2019; 34(3): 3-7.|