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6.BRIEF RESUME OF THE INTENDED WORK:

6.1 NEED FOR THE STUDY:

Lumbar disc prolapse is a common cause of low back pain and nerve root pain(sciatica)1. Ninety percent of acute attacks of sciatica settle with conservative management 1. The usual indications for surgery is to provide more rapid relief of pain and disability in patients who do not recover even after a trial of six weeks of conservative treatment, the presence of cauda equina syndrome and progressive motor deficit 1,2,3. Presently standard of surgical care remains the minimally invasive spinal procedure for lumbar disc prolapse, which is focussed on minimizing the soft tissue dissections, creating a laminotomy without creating instability, safely retracting the dura and individual nerve root and finally excising the disc herniation. One of these is microdiscectomy which uses the operating microscope. Over years microdiscectomy has gradually evolved to become a gold standard operative technique for lumbar disc herniation 1,2,3. Further advances were made with adoption of an endoscope in conventional lumbar discectomy i.e. endoscopic discectomy which combines spinal endoscopy and techniques used in microdiscectomy. This study is mainly aimed at evaluating the surgical outcome and complications of endoscopic discectomy done for single level lumbar disc herniation.

6.2 REVIEW OF LITERATURE:

In the past, patients with lumbar disc herniation were treated with laminectomy and discectomy which required larger incisions, muscle stripping, more operating time, anaesthesia, hospitalization and longer recovery period. Disc surgery has evolved towards minimally invasive procedures which includes chemonucleolysis with papain 5, percutaneous laser discectomy and intradiscal electrothermy.

However these are mainly intradiscal procedures and cannot be used for extruded disc fragments. Endoscopic discectomy is a procedure which directly deals with the offending prolapsed or extruded disc fragment and decompress the nerve root. Studies have shown that endoscopic discectomy has several advantages over microdiscectomy which includes smaller incision, less dissection, lesser post operative pain, early ambulation, short hospital stay and shorter time to return to work 6.

3. AIM OF THE STUDY To evaluate the surgical outcomes and complications of endoscopic discectomy done for single level lumbar disc herniation.

7. MATERIALS AND METHODS:

A minimum of 25 patients of lumbar disc herniation coming to Neuro surgery department of M S Ramaiah Hospitals between 2007 to 2010 will be taken up for the study.

Preoperative MRI will be done for all patients. All patients will be given a trial of conservative treatment for a minimum 6 weeks before surgery which included bed rest, analgesics, muscle relaxants and physiotherapy except for patients with neurological deficits in the form of radiculopathy or cauda equina syndrome. Outcome assessment will be made by using modified macnab criteria on post operative day 7 and on the post operative period between 3 to 6 months. The patients ability to return to the previous employment is measure of the success of surgical procedure.

7.1 DIAGNOSIS OF LUMBAR DISC HERNIATION:

Clinical Features:

Symptoms : History of fall or lifting heavy weights sometimes preceeds the onset of symptoms.

a) Leg pain: Nerve root irritation or compression produces pain in the distribution of the affected root and this extends below the mid-calf. Coughing, sneezing or straining aggravates the leg pain. If compression causes severe root damage the leg pain may disappear as neurological signs develop.

b) Paraesthesias: Numbness or tingling occurs in the distribution of the affected root.

c) Weakness of the Muscles may also occur depending on the affected nerve root.

Mechanical signs:

a) Spinal movements are restricted.

b) Scoliosis is often present.

c) Normal lumbar lordosis may be lost.

d) Point of tenderness may be present over the spinous process at the level of the disc involved.

e) Straight leg raising test : L5 & S1 nerve root compression causes limitation of movement to less than 60o from the horizontal plane and produces pain down the back of the leg . Dorsiflexion of the foot while the leg elevated aggravates the pain. Contralateral leg pain produced by straight leg raising should be regarded as pathognomonic of a herniated intervertebral disc.

f) Reverse leg raising test (femoral stretch test) : This test is for irritation of higher nerve roots (L4 and above).

Neurological deficits :

Depends upon the predominant nerve root involved.

a) Unilateral disc herniation between L3 & L4 results in compression of L4 nerve root.

L4 nerve root compression :

i) Motor weakness : Quadriceps muscle, hip adductors, tibialis anterior muscle weakness.

ii) Reflex : Patellar tendon reflex is diminished or absent

iii) Sensory deficit : Posterolateral thigh, anterior aspect of knee and medial aspect of leg.

b) Unilateral disc herniation between L4 & L5 results in compression of L5 nerve root.

L5 nerve root compression :

i) Motor weakness : Extensor hallucis longus, Gluteus medius muscle, extensor digitorum longus and brevis.

ii) Reflex : Usually none, diminished tibialis posterior reflex which is difficult to elicit.

iii) Sensory deficit : Anterolateral aspect of the leg, dorsum of the foot and great toe.

c) Unilateral disc herniation between L5 & S1 results in compression of S1 nerve root.

S1 nerve root compression :

i) Motor weakness : peroneus longus and brevis, Gastrocnemius-soleus complex, Gluteus maximus.

ii) Reflex : Ankle jerk diminished or absent.

iii) Sensory deficit : Lateral malleolus, lateral aspect of foot and sole including heel, web of fourth and fifth toes.

Investigation: MRI of the spine is the investigation of choice.Sagittal views combined with axial views at the appropriate level will demonstrate disc herniation.

Normally on T1 weighted images, bone is of intermediate to high signal intensity,

depending on the degree of fatty marrow. Discs reflects intermediate signal intensity. The nerve roots, which also reflects intermediate signal intensity, are surrounded by low signal intensity CSF, which is inturn enveloped by high signal intensity fat.

MRI Findings:

-Best diagnostic clue is the anterior extradural mass contiguous with disc

space extending into spinal canal.

-T1W1 : Isointense to parent disc.

-T2W1 : Iso to hyperintense to parent disc, depending on disc hydration.

-Disc height loss.

-Enhancing nerve root likely due to venous congestion with or without

inflammation due to variable extent of nerve impingement.

Abnormal discs can be classified as Bulging or Herniated. Further Herniated discs can be subclassified as Protruded, Extruded and Sequestered.

BULGING DISC : An annular bulge represents an extension of the disc margin beyond the confines of the adjacent vertebral end plate. The annular fibres are stretched but intact.

PROTRUDED DISC : When some of the inner fibres of the annular tear but the outer fibres remain intact, the nucleus can focally herniate through the inner tear.

EXTRUDED DISC : When the nucleus pulposus herniates through a complete tear

of the annulus fibrosis and is contained only by the posterior longitudinal ligament,

however herniated segment remains attached to the parent disc.

SEQUESTERED DISC : When an extruded nucleus breaks free of the parent disc,

It is terned a sequestered disc or free fragment. Sequestered portion may or may not

be contained by the posterior longitudinal ligament.

7.2 SOURCE OF DATA:

Patients of single level lumbar disc herniation coming to Neurosurgery department of M.S.Ramaiah hospitals will be taken up for the study.

7.3 STUDY DESIGN:

Prospective study

7.4 INCLUSION CRITERIA:

-Patients with clinical features suggestive of lumbar disc herniation with MRI showing single level lumbar disc herniation to one side were preferred, however central disc herniation with symptoms in one limb were also included.

- Age< 70 years

7.5 EXCLUSION CRITERIA:

- Patients with clinical features suggestive of lumbar disc herniation with MRI showing multiple level lumbar disc herniation.

- Associated lumbar canal stenosis and ligamentum flavum hypertrophy

- Patients with central disc herniation with symptoms in both lower limbs

- Age > 70 years

- Patients with space occupying lesions such as an abscess, tumor, epidural hematoma, were excluded.

6. STATISTICAL ANALYSIS :

Descriptive statistics will be used to analyze the outcome of the study

7.7 Does this study require any investigations or interventions to be conducted

on patients or other humans or animals.If so ,describe briefly.

- Routine preoperative investigations: Haemoglobin%, Total WBC count, Differential WBC count, Erythrocyte sedimentation rate, Random Blood Sugar, Bleeding time, Clotting time, Blood Urea nitrogen, Serum creatinine, Serum electrolytes.

-Special investigations: MRI of spine

-No animals will be used in this study.

7.8 Has ethical clearance been obtained from your instituition:

YES, ethical clearance has been obtained from the institution and the relevant certificate has been enclosed.

8. REFERENCES

1. Caspar W. A new surgical procedure for lumbar disc herniation causing less tissue damage through microsurgical approach. In: Wullenweber R, Brock M, J, Klinger M, Spoerri O, editors. Advances in Neurosurgery. Springer-Verlag: Berlin; 1977. p. 74-7.

2. Maroon JC. Current concepts in minimally invasive discectomy. Neurosurgery 2002;51:S137-45.

.

3. Nakagawa H, Kamimura M, Uchiyama S, Takahara K, Itsubo T, Miyasaka T. Microendoscopic discectomy (MED) for lumbar disc prolapse. J Clin Neurosci 2003;10:231-5.

4. Finneson BE. Lumbar Disc Excision. In: Schmidek HH, Sweet WH, editors. Operative Neurosurgical Techniques. 3rd ed. WB Saunders: Philadelphia; 1995. p. 1905-23.

5. Smith L, Brown JE. Treatment of lumbar intervertebral disc lesion by direct injection of chymopapain. J Bone Joint Surg Br 1967;49:502-19.

6. Yasargil MG. Microsurgical operation for herniated lumbar disc. In: Wullenweber R, Brock M, Hamer J, Klinger M, Spoerri O, editors. Advances in Neurosurgery. Springer-Verlag: Berlin; 1977. p. 81.

9. Signature of the candidate :

10. Remarks of the guide : It’s a good study

10.1 Name and designation of the guide : DR.A.C.ASHOK MS , DNB

Professor and Head of unit,

Surgery Unit-III,

Dept. of General Surgery,

M.S.R.M.C.T.H,

Bangalore.

10.2 Signature of the guide :

11. Remarks of the Co-guide: This is a good study to assess the surgical

outcomes in single level lumbar disc prolapse

11.1 Name and designation of the

Co-guide : DR. BALAJI PAI MBBS, DNBE

Professor of Neuro Surgery

M.S.R.M.C.T.H,

Bangalore.

11.2 Signature of the Co-guide :

12. Name and designation of the H.O.D : DR.M.R.SREEVATHSA M S

Professor and

Head of the Department

Dept. of General Surgery,

M.S.R.M.C.T.H,

Bangalore.

12.1 Signature of the H.O.D :

13. Remarks of the Principal :

13.1 Signature of the Principal:

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