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SPINE Table of Contents   
Year : 2006  |  Volume : 40  |  Issue : 2  |  Page : 86-89
Lumbar disc excision through fenestration


Department of Orthopaedics, Physical Medicine, Paraplegia and Rehabilitation, Pt BD Sharma Post Graduate Institute of Medical Sciences, Rohtak, India

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   Abstract 

Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases.
Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method.
Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value<0.001, paired t test). No significant complications were recorded.
Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

Keywords: Prolapsed intervertebral disc; Sciatica; Fenestration; Discectomy.

How to cite this article:
Sangwan S S, Kundu Z S, Singh R, Kamboj P, Siwach R C, Aggarwal P. Lumbar disc excision through fenestration. Indian J Orthop 2006;40:86-9

How to cite this URL:
Sangwan S S, Kundu Z S, Singh R, Kamboj P, Siwach R C, Aggarwal P. Lumbar disc excision through fenestration. Indian J Orthop [serial online] 2006 [cited 2019 Jul 20];40:86-9. Available from: http://www.ijoonline.com/text.asp?2006/40/2/86/34446

   Introduction Top


In orthopedic practice patients having lesions of lumbo­sacral region causing low backache with sciatica are not uncommon since the beginning of recorded history. The first disc prolapse operation falsely accredited to Mixter and Barr had been conducted by Oppenhein and Krause in Berlin but interpreted it as an enchondroma of spinal disc [1],[2] . Mixter and Barr's classical paper "Rupture of intervertebral disc with involvement of spinal canal" opened an era of systematic diagnosis and operative treatment of lumber disc prolapse. Their operative approach was an extensive laminectomy. [3]

Shortly afterwards hemilaminectomy became the favourite procedure in cases with unilateral symptoms. Love described extradural removal of herniated disc and devised interlaminar fenestration for treatment of lumber disc prolapse. [4] Refinement of fenestration technique was described by Williams who coined the term "Conservative surgical approach to the virgin herniated disc" which required the use of operating microscope to facilitate better visualization of dural sac, nerve roots and other interspinal structures including disc [5] . The advantages of fenestration and interlaminar approach has been demonstrated [6],[7],[8] . Mishra et al compared laminectomy and fenestration for disc excision and concluded the superiority of later approach in respect to early postoperative mobilization, early return to work and low incidence of postoperative backache as it is less extensive [9] . It is very safe, effective and reliable surgical technique for treating properly selected patients with herniated disc. This approach is free from spinal instability and membrane formation resulting from laminectomy10.The recent techniques like percutaneous lumbar disc decompression (PLDD), percutaneous endoscopic lumbar discectomy (PELD) and Young endoscopic spine system (YESS) need lots of expertise, experience and expensive equipments which are not available at every center. [11],[12] Hence disc excision through fenestration is the procedure which can be performed by majority of orthopaedic surgeons even in small peripheral centers.


   Materials and methods Top


Twenty-six patients with signs and symptoms of prolapsed lumbar intervertebral disc who failed to respond to conservative treatment of minimum 6 weeks duration were studied prospectively. Patients with PIVD who were having neurological deficits and intractable pain not relieved by adequate conservative trial and patients with bladder and bowel involvement (cauda-equina syndrome) were assessed preoperatively regarding informative history through general and neurological examination and were subjected to magnetic resonance imaging scan (MRI). The results of imaging were correlated with physical findings and symptomatology of the patients. All clinico-radiologically proven cases were subjected to surgery.

All patients were operated in knee-chest position under general anaesthesia. In 12 cases lower 3rd part of upper lamina or upper 3rd of lower lamina was cut to enlarge a fenestration for clear view. Adherent part of the disc was not removed. Meticulous hemostasis was achieved with bipolar coagulation and surgicel. In cases of inadvertent dural tears, accessible ones were sutured with non-absorbable sutures while inaccessible ones were sealed by fibrin glue and epidural fat was placed over the nerve root to prevent postoperative adhesions. Incision was closed in layers without negative suction drains.

Postoperatively patients were allowed up on first postoperative day. Gradual walking was encouraged, prolonged stooping and flexion was avoided. Lifting, bending and stooping prohibited for 6 weeks. Patients who were heavy laborers or long distance drivers were off work until 12 weeks and then advised to modify their duties. All patients were advised a regular postoperative back exercise program after 3 weeks.

Statistical analysis was performed with statistical software (version 12.0 for windows, Chicago, Illinois) and data were evaluated by paired student t test. Significance was accepted at p-value < 0.01.


   Results Top


Out of 26 patients 18 were males and 8 were females. The average age was 38.22 years ranging from 25-50 years. Thirteen patients were sedentary workers. Relevant examination findings of patients were as per [Table - 1]. The most common level of involvement was L 5 -S 1 followed by L 4 -L 5 . Central or posterocentral position of the prolapsed disc was most common followed by paracentral, posterolateral and lateral in that order. Fifteen patients had left sided symptoms while eleven had right sided. The average duration of preoperative back pain was 14.6 months and that of preoperative leg pain was 10 months. The average duration of conservative management was less than 6 months in 17 patients and rest had more than six months. Intraoperatively eleven patients had massive disc prolapse. Average postoperative hospital stay was 4.8 days.

In our study we assessed pain according to VAS scale [13] . The preoperative mean±SD VAS score was 9.34± 0.84 which improved to 2.19±0.84 postoperatively. A paired student t­test showed that the above changes were statistically significant (p<0.001), which shows a significant reduction in patient's perception of pain.

The follow up data was analyzed using modified Macnab criteria [14] and patient based outcome studies using SF-36 [15] .

Based on modified Macnab criteria 17 patients showed excellent, 6 good and 2 fair results. One poor result was due to persistent root pain. Based on SF-36 questionnaire for comparing quality of life preoperatively Vs postoperative on eight domains, all the eight domains showed statistically significant findings (p<0.001). Except for bodily pain, general health, physical function and social function, all other domains showed positive improvements with transformed scores postoperatively.

Seventeen patients in our study returned to work in less than one month after surgery. Eighteen patients returned to change their original work while 8 patients had to their nature of work.

There was inadvertent dural tear in three patients. In two cases dural rent repair was done under vision, while in the 3 rd case tissue sealant glue was used. All three patients recovered uneventfully. Two patients had temporary retention of urine after the surgery which relieved by single catheterization. Three patients complained postoperative headache, relieved by intravenous saline hydration and analgesics. Transient back pain was complained by four patients postoperatively, relieved by analgesics. No other major complications like DVT, pulmonary embolism, nerve root injury, retroperitoneal injury or wound infection occurred in our study.


   Discussion Top


Prolapsed intervertebral disc occurs in about 5-10% of all backache patients and is a common cause of sciatica. Even a small herniated disc in the presence of a narrow spinal canal can be responsible for the compression of cauda equina and its roots. The standard treatment of lumber disc prolapse has been surgical excision of the disc, though the methods of discectomy vary. The traditional view has been that wide laminectomy produces increased morbidity compared to less extensive procedures like inter-laminar fenestration [16] .

Most cases of sciatica due to intervertebral disc lesions were in fact partial cauda equina lesions, mostly unilateral and characterized by muscular weakness, wasting, reflex abnormalities and sensory impairment referable to compression of one or more nerve roots. The radiating pain in leg did not differ appreciably in L 4 -L 5 and L 5 -S 1 disc lesions. In both groups the pain radiated along the posterior aspect of thigh and calf. Quite frequently these patients complained of tingling and numbness along sciatic nerve distribution. Out of 26 cases in our study 21 were having neurological deficit, out of which 5 had cauda equina compression and bladder involvement.

Love devised inter-laminar fenestration [4] . Refinement of fenestration technique was described by William who used an operating microscope to facilitate better visualization of dural sac, nerve roots and other inter-spinal structures including the prolapsed disc [5] .

Results of this study, state that the lumbar discectomy performed with a limited disc excision by fenestration is a safe, effective and reliable method for treating selected patients with herniated lumbar discs. No patients in this study deteriorated after surgery. The length of a patient's recovery period after surgery appeared to be strongly influenced by environmental factors and patient's motivation. In majority of patients with good results, the preoperative sciatic symptoms improved within first three days after surgery.

The approach herein differs from microdiscectomy only in extent of exposure. The disc removal per se in both is limited. Incision into the annulus fibrosus was necessary only when a protruded disc herniation was identified. Additional exposure in fenestration has the advantage of correcting lateral recess stenosis. Surgeon must be prepared to perform foraminotomy or undercutting of upper or lower lamina in addition to lumbar disectomy if the nerve root remains tight after disc excision.

The incidence of complications in our study involving 26 operations such as dural tears, postoperative retention of urine, headache, and backache is low. Other complications reported [18],[19],[20] did not occur in our study i.e. wound infection, discitis, increased neurological deficit, nerve root injury, pulmonary embolism, retroperitoneal injury or vascular injury etc.

The straight forward test to measure pain is probably simply asking patient to quantify it on Visual analog scale (VAS) [18] . This has been used in previous studies for effective monitoring of changes in pain and functional capacity after spinal surgery. On the VAS patient indicates pain intensity on a typical day by marking a line from 0-10 corresponding to pain level. In our study the preoperative mean ± SD VAS score was 9.34±0.84 and postoperative mean ± SD VAS score was 2.19±0.84 on a scale of 10. A paired t-test showed that the above changes were statistically significant (p<0.001), which demonstrated a significant reduction in the patient's perception of pain and improved functional capacity after surgery.

We conclude that the procedure of fenestration and open disc excision under direct vision offers the complete visualization of nerve root and complete removal of the offending disc along with loose fragments. In comparison to microdiscectomy, disc excision by fenestration has yielded almost comparable results, except for slight more lifting of paraspinal muscles, though they fall back well in their place with meticulous closure. Further microdiscectomy is the procedure which needs greater know-how and expertise in instrumentation and techniques and is less cost effective. In the peripheral institutions fenestration with disc excision is quite a reasonable method to surgically treat the indicated cases of prolapsed disc and this procedure can be well performed even by an average spinal surgeon with adequate experience in the field of disc surgery.

 
   References Top

1.Hedtmann A. Das sog. Postdiskotomiessyndrom: Fehlschlage der Bandscheiben-operation? Z Orthop. 1992; 130: 456-66.  Back to cited text no. 1    
2.Loew F, Casper W. Surgical approach to lumbar disc herniations. Adv.standards Neurosurg. 1978; 5: 153-74.  Back to cited text no. 2    
3.Mixter WJ, Barr JS. Rupture of intervertebral discs with involvement of spinal canal. New Eng J Med. 1934; 211: 210-14.  Back to cited text no. 3    
4.Love JG. Root pain resulting from intraspinal protrusion of vertebral discs: diagnosis and treatment. J Bone Joint Surg.1939; 19: 776-80.  Back to cited text no. 4    
5.Williams RW. Micro lumbar disectomy; a conservative surgicalapproach to the virgin herniated lumbar disc. Spine. 1978; 3:17582.  Back to cited text no. 5    
6.Nagi ON, Sethi A, Gill SS. Early results of discectomy by fenestration technique in lumbar disc prolapse. Ind J Orthop. 1985; 19(1): 15-9.  Back to cited text no. 6    
7.Casper W,Campball B, Barbier DD et al. The Caspar microsurgical discectomy and comparison with a conventional standard lumbar disc procedure. Neurosurgery. 1991; 28: 78-87.  Back to cited text no. 7    
8.Nijhawan VK, Maini PS, Chadha NS, Magu NK, Magu S. Lumbar disc surgery. Ind J Orthop. 1991; 25(1): 5-7.  Back to cited text no. 8    
9.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.  Back to cited text no. 9    
10.Garg M, Kumar S. Interlaminar discectomy and selective foraminotomy in lumbar disc herniation. J Orthop Surg (HongKong). 2001 Dec; 9 (2):15-18.  Back to cited text no. 10    
11.Kleinpeter G, Markowitsch MM, Bock F. Percutaneous endoscopic lumbar discectomy: Minimally invasive, but perhaps only minimally use­ful? Surg Neurol.1995;43(6):534-539.  Back to cited text no. 11    
12.Yeung AT. The evolution of percutaneous spinal endoscopy and discectomy: State of the art. Mt Sinai J Med. 2000; 67(4):327-332.  Back to cited text no. 12    
13.Huskisson EC. Measurement of Pain. Lancet. 1974; 2(7889):1127 31.  Back to cited text no. 13    
14.Agarwal S, Bhagwat AS. Ho:Yag laser-assisted lumbar disc decom­pression: A minimally invasive procedure under local anaesthesia. Neurol India. 2003; 51(1): 35-38.  Back to cited text no. 14    
15.Ware JE, Sherbourne CD. The MOS 36-item short form health survey (SF-36). Med Care. 1992; 30(6): 473-83.  Back to cited text no. 15    
16.O'Connell JEA. Protrusions of the lumbar intervertebral discs. J Bone Joint Surg (Br). 1951;33:8-30.  Back to cited text no. 16    
17.Barbara M, Knop J, James FZ, Ken YH, Bradford D. Anatomic position of a herniated nucleus pulposus predicts the outcome of lumbar disectomy. J Spinal Dis. 1996; 9(3): 246-50.  Back to cited text no. 17    
18.Hudgins WR. The role of microdiscectomy. Orthop Clin North Am.1983; 14:589-603.  Back to cited text no. 18    
19.Ebeling U,Reichenberg W,Reulen HJ. Results of microsurgical lum­bar discectomy: Review of 485 patients. . 1986;81 :45-52.  Back to cited text no. 19    
20.Nystrom B. Experience of microsurgical compared to conventional technique in lumbar disc operations. Acta Neurol Scand.1987; 76:129-­41.  Back to cited text no. 20    

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Correspondence Address:
Z S Kundu
31/9J, Medical Enclave, Pt. BD Sharma PGIMS, Rohtak 124001
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0019-5413.34446

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