Posterolateral interbody Fusion with Laminoplasty in the treatment of lumbar isthmic spondylolisthesis. A prospective clinical study

IntroductionThe technique for the surgical treatment of isthmic spondylolisthesis (ISL) is stillcontroversial. Different opinions have been expressed by various authors on thetiming, type of surgery, type of the graft used as well as on whether reduction shouldbe applied or not value of reduction. In light of these data describe our technique in thetreatment of ISL and its outcomes.MethodsBetween January 2013 and December 2016, we examined 40 consecutive patients thathad been operated in our clinic due to ISL. The patients have been assessed clinicallyand radiologically. The same posterior surgical technique was used in all patients(interbody fusion using bone substitute, reduction of the olisthesis and reinsertion ofthe lamina).Surgical techniqueIn prone position, after exposure of the spine posteriorly and transpedicular screwfixation of the affected segment, the lamina of the affected level was removed en-blocthrough the Facet joint and site of lysis on both sides. Decompression of the nerveroots on both sides followed by discectomy and the endplates were prepared for bonesubstitute and cage. Partial reduction of the olisthesis could be achieved through thediscectomy and additional reduction through the application of lordotic rods. Finallyafter preparation of the lamina and removal of the cartilage on the joint surfaces thelamina was placed and fixed through small screws 2.7mm through the facet joint onboth sides.Results The mean age 24 females and 16 males was 53.2 years (78-18). The maincomplaint at the time of presentation was low back pain (mean VAS 10/5.9) in 36patients with mean duration of 11.9 months. Leg pain was also in 17 cases; L5 radicularpain in14 of them. Two patients had foot weakness due to foraminal disc herniation.Olisthesis grade I was in 22 patients, grade II in 14 and grade III in 4 cases. The techniquewas performed in 30 patients for L5/S1, in 8 patients for 5/4, in 2 patients for L-4S1.Fusion of adjacent degenerative level was in 7 cases. Mean operative time was 182min. and blood loss of 630 ml. Complete reposition could be obtained in 33 patients. Two patients had dural tears intraoperatively, one patient had foot weakness postop.,improved completely with the first postop. week and 2 had superficial wound infection;one needed wound revision. Solid fusion found in 37 patients at the last FU; 2 patientsdeveloped symptomatic screw loosening of L5, who had to be re-operated. VASreduced to 10/3 before the discharge and to 1,2 at the last FU (mean of 20.5 months).ConclusionRemoval of the lamina facilitate decompression of the nerve roots and enablesthe reduction of Olisthesis. The use of bone substitute prevents the donor sitecomplications. The laminoplasty preserve the osseous structures of the posteriorcolumn and therefore prevents scar formation by inhibition blood collection in theparavertebral muscle. It also facilitates performing the revision surgeries.