Background:Various modalities of treatment from standard discectomy, microdiscectomy, percutaneous discectomy, and transforaminal endoscopic discectomy have been in use for lumbar intervertebral disc prolapse. The access to spine is kept to a minimum without stripping paraspinal muscles minimizing muscle damage by posterior interlaminar endoscopic approach. The aim of this study was to evaluate technical problems, complications, and overall initial results of microendoscopic discectomy.Materials and Methods:First 100 consecutive cases aged 19-65 years operated by microendoscopic dissectomy between August 2002 – December 2005 are reported. All patients with single nerve root lesions including sequestrated or migrated and selected central disc at L4-5 and L5-S1 were included. The patients with bilateral radiculopathy were excluded. All patients had preoperative MRI and first 11 patients had postoperative MRI to check the adequacy of decompression. Diagnostic selective nerve root blocks were done in selective cases to isolate the single root lesion when MRI was inconclusive (n=7). All patients were operated by a single surgeon with the Metrx system (Medtronics). 97 were operated by 18-mm ports, and only three patients were operated by 16-mm ports. Postoperatively, all patients were mobilized as soon as the pain subsided and discharged within 24–48 h postsurgery. Patients were evaluated for technical problems, complications, and overall results by modified Macnab criteria. Patients were followed up at 2, 6, and 12 weeks.Results:The mean follow up was 12 months (range 3 months – 4 years). Open conversion was required in one patient with suspected root damage. Peroperatively single facet removal was done in 5 initial cases. Minor dural punctures occurred in seven cases and root damage in one case. The average surgical time was 70 min (range 25-210 min). Average blood loss was 20-30 ml. Technical difficulties encountered in initial 25 cases were insertion of guide pin, image orientation, peroperative dissection and bleeding problems, and reaching wrong levels suggestive of a definitive learning curve. Postoperative MRI (n=11) showed complete decompression. Overall 91% of patients had good-to-excellent results, with four patients having recurrence of whom three were reoperated. Four patients had postoperative discitis. One of the patients required fusion for discitis and rest were managed conservatively. One patient had root damage to L5 root that had paresthesia in L5 region even on 4 years of follow-up.Conclusion:Microendoscopic discectomy is minimally invasive procedure for discectomy with early encouraging results. Once definite learning curve was over and expertise is acquired, the results of this procedure are acceptable safe and effective.

Background:The use of minimally invasive surgical (MIS) techniques represents the most recent modification of methods used to achieve lumbar interbody fusion. The advantages of minimally invasive spinal instrumentation techniques are less soft tissue injury, reduced blood loss, less postoperative pain and shorter hospital stay while achieving clinical outcomes comparable with equivalent open procedure. The aim was to study the clinicoradiological outcome of minimally invasive transforaminal lumbar interbody fusion.Materials and Methods:This prospective study was conducted on 23 patients, 17 females and 6 males, who underwent MIS-transforaminal lumbar interbody fusion (TLIF) followed up for a mean 15 months. The subjects were evaluated for clinical and radiological outcome who were manifested by back pain alone (n = 4) or back pain with leg pain (n = 19) associated with a primary diagnosis of degenerative spondylolisthesis, massive disc herniation, lumbar stenosis, recurrent disc herniation or degenerative disc disease. Paraspinal approach was used in all patients. The clinical outcome was assessed using the revised Oswestry disability index and Macnab criteria.Results:The mean age of subjects was 55.45 years. L4-L5 level was operated in 14 subjects, L5-S1 in 7 subjects; L3-L4 and double level was fixed in 1 patient each. L4-L5 degenerative listhesis was the most common indication (n = 12). Average operative time was 3 h. Fourteen patients had excellent results, a good result in 5 subjects, 2 subjects had fair results and 2 had poor results. Three patients had persistent back pain, 4 patients had residual numbness or radiculopathy. All patients had a radiological union except for 1 patient.Conclusion:The study demonstrates a good clinicoradiological outcome of minimally invasive TLIF. It is also superior in terms of postoperative back pain, blood loss, hospital stay, recovery time as well as medication use.

Objective: To study efficacy of minimally invasive oblique lumbar interbody fusion (MIS OLIF) to achieve indirect decompression in degenerative lumbar spine disorders. To find out amount of indirect decompression achieved by assessing clinical and radiological outcomes. To find out limitations of indirect decompression. Methods: OLIF was carried out in 60 segments/45 patients having degenerative lumbar spine disorders from May 2016 to April 2018. Patients with infection, trauma, lumbar disc prolapse and listhesis >grade 3 were excluded. 53 segments had posterior and 7 segments had anterior fixation. Auto graft was used in 21 and artificial bone graft in 24 patients. Indirect decompression by MIS OLIF was achieved in all patients. Neuromonitioring was not used. Clinical assessment was done using Modified Macnab's criteria. Radiological assessment was done on X-rays and MRI. Percentage improvement in foraminal height, disc height, segmental lordosis, spinal canal area and reduction in listhesis were measured. Statistical assessment was done using Paired't' test. Results: 60 segments of 45 consecutive patients were operated with 15 of them male and 30 female. Average age was 63 years. Minimum follow-up was for 1 month and maximum follow-up was for 18 months with average of 11 months. Single segment fusion was done in 31, 2 segment fusion in 13 and 3 segment fusion in 1 patient. Clinically 33 (73.33%) had excellent, 11 (24.44%) had good & 1 (2.22%) had fair outcomes. None required direct decompression. Radiologically; foraminal height improved by 26.27%, disc height 92.1%, segmental lordosis 3.4° and listhesis reduction was 6.8°, 41 segments studied on MRI had improvement in spinal canal area of 42.7%. Conclusion: Indirect decompression by MIS OLIF is effective in decompressing the spinal canal with good radiological and clinical out comes. Direct decompression is avoidable with help of interbody distraction using OLIF particularly in patients with Schizas grade A, B, and C of lumbar spinal stenosis.

The anatomic corridor is defined by different studies in the western population but the exact corridor for the Indian population is never been studied. Objective of the study was to define anatomical corridor for preoperative assessment of Oblique Lumbar Interbody Fusion (OLIF) in the Indian population. Methods: We selected imaging data from 180 adults (90 males and 90 females) who underwent MRI. The windows studied at L1-2 to L4-5 levels were vascular window, bare window, psoas major window, and operative window. The bare window was further analysed by dividing it into three groups. Group 1 with no window, group 2 with 0 to 5 mm window, and group 3 with more than 5 mm. Statistical analysis was carried out by unpaired t-test. Results: The bare window was largest at L1-2 (1.29 ± 0.53 cm) and smallest at L4-5 (0.79 ± 0.52 cm). The psoas major window was largest at L3-4 (1.24 ± 0.38 cm) and smallest at L1-2 (0.45 ±0.47 cm). The operative window was largest at L3-4 (2.4 ±0.47 cm) and smallest at L4-5 (1.72 ± 0.67 cm). In 10.56% of patients at L4-5, there was no bare window and OLIF cannot be performed in these patients. Conclusion: Bare window gradually decreases from L12 to L45 levels. In the majority of patients at L12, L23, and L34 there is adequate bare window and OLIF can be safely performed. In 10.56% of patients, the bare window for performing OLIF does not exist at L45 and OLIF may not be feasible in these patients.

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