Lumbar Interverterbral Disc Prolapse ( PLID ) Surgery and Our Experiences

Background: Back pain and sciatica are very common in adult persons. These cause a great loss of working hours with financial loss of individual and the nation. Very careful evaluation must be done to treat these patients. Injudicious treatment, whether medical or surgical, may aggravate the sufferings. Objective: To study immediate and long term effect of the prolapsed intervertebral disc surgery. Materials and Methods: This observational study was done in Enam Medical College & Hospital, Savar, Dhaka during January 2007 to June 2011. Sixty four patients operated during this period for prolapsed lumbar intervertebral disc were included in the study. Fifty six (88%) were male and 8 (12%) were female. Age range was 30 to 50 years. Most of the patients presented with back pain and sciatica with no definite history of trauma or weight lifting. Diagnosis was confirmed by MRI. Results: Sixty (94%) patients had no pain after surgery and only 4 patients had occasional pain. Conclusion: Maintenance of strict criteria for the surgery yields very good result.

Humans have been plagued by back and leg pain since the beginning of the recorded history.Oppenheins and Krause performed the first successful surgical excision of a herniated intervertebral disc in 1909.Unfortunately they could not recognize the excised tissue as disc material and interpreted it as an enchondroma. 1Dandy reported removal of disc tumour or chordoma from patients with sciatica in 1929. 2 In 1932 Barr attributed the source of sciatica to the herniated lumbar disc. 3In 1939 Seemes presented a new procedure to remove the ruptured interverterbral disc that included subtotal laminectomy and retraction of the dural sac to expose and remove the ruptured disc with the patient under local anaesthesia. 4Love in the same technic have done successful removal of disc independently. 5Standard procedure for disc removal was total laminectomy followed by transdural approach of the disc. 1 Mixter and Barr 6 proposed lumbar fusion after excision of the disc to prevent instability.But Frymoyer et al 7  the patients was 30-50 years.They presented with acute back pain and sciatica; 4 patients came with foot drop (2 unilateral and 2 bilateral) along with back pain and sciatica.We examined them clinically.All patients were positive for straight leg raising (SLR) test.Two patients had incontinence of urine and perianal hypoaesthesia.
On examination, there was no muscle wasting in any of our patients.Forty patients had hypoaesthesia on the lateral aspect of the foot and 20 patients had hypoaesthesia on the medial aspect.Thirty six patients had weakness of extensor hallucis longus muscles of the affected limb.Radiography of lumbosacral spine in antero-posterior and lateral views showed loss of normal lordotic curvature.All the patients except those with foot drop were given adequate conservative treatment.We treated them by nonsteroid anti-inflammatory drugs (NSAIDs) and physiotherapy for 3 weeks.Magnetic resonance imaging (MRI) of lumbosacral spine was done of those patients who did not improve with 3 weeks conservative treatment.
MRI confirmed single level disc prolapse in 60 patients and double level prolapse in 4 patients.Thirty six (63%) patients had left-sided disc prolapse, in 24 (31%) cases it was right-sided and in 4 (6%) cases it was bilateral.All patients were operated under general anaesthesia by classical procedure.Required investigations were done for anaesthetic fitness.
All patients were operated in prone position, keeping sand bolster under the chest.All were operated by posterior midline incision and classical fenestration was done by removing the ligamentum flavum and part of the upper lamina as much as required.After retraction of the dural sac and nerve root medially, the protruded disc material was exenterated by pituitary forceps.After haemostasis the wound was closed layer by layer.Blood transfusion was not required in any case.There was no complication during operation or postoperatively.Patients were discharged from the hospital within 6 to 10 days; stitches were removed after 12 to 14 days.They were taught back extension exercises during hospital stay and advised for exercises at home.They were advised to refrain from lifting heavy weights for at least 3 months.

Results
All patients were observed periodically in outdoor.Total 64 patients were operated.Sixty (94%) cases were completely cured from their back pain and sciatica.In our follow-up time 2 cases with foot drop recovered completely within 6 months.All these 60 patients returned to their previous job.The remaining 4 (6%) patients who were a bit older and had more than one level disc prolapse returned to their job, but had periodic back pain without sciatica.They required NSAIDs and physiotherapy.

Fig 1 .
Fig 1. MRI of lumbar spine shows disc prolapse in longitudinal section and others indicate that there is little if any advantage to the addition of spinal fusion.Causes of failed surgery are wrong diagnosis, wrong level of operation, recurrence of disc prolapse at the same level or another level.