Impact of Spinal Surgery on Intrathecal Nusinersen Injections in Pediatric Spinal Muscular Atrophy.

BACKGROUND: Complex spinal deformities necessitate surgical interventions that may intervene with intrathecal injections in patients with spinal muscular atrophy (SMA). This study aimed to determine the effect of spinal deformity correction surgery on nusinersen administration. METHODS: Pediatric patients with SMA, operated by a single surgeon, either via magnetically controlled growing rod (MCGR) or definitive fusion (DF) with skip instrumentation, were evaluated retrospectively in terms of safety and feasibility of intrathecal injections. Patients' and their parents' perspectives were evaluated through a questionnaire regarding any shift in the setting of injections. RESULTS: Fourteen patients with 15 spinal surgeries (10 MCGR and 5 DF) were included. Eleven patients received intrathecal treatment both before and after the surgery. Preoperative (n=3) and postoperative (n=9) fluoroscopic guidance was required leading to a shift in the application settings in 6 patients. Of 106 preoperative injections, 15% required fluoroscopy and 2% required anesthesia. Postoperatively, of 88 injections, 73% required fluoroscopy and 26% required anesthesia. No patients discontinued intrathecal injections due to technical difficulties associated with the spinal surgery. CONCLUSIONS: This study demonstrates that spinal surgery does not prevent safe and successful intrathecal nusinersen injections. In the DF group, the skip instrumentation technique provided access to interlaminal space for intrathecal injections. In either surgical group, no further auxillary approach was required. Modifications in the injection technique require an institutional approach, and concerns of patients and their families should be addressed accordingly. LEVEL OF EVIDENCE: IV.

Does the Sleeper Plate Application for Temporary Epiphysiodesis Make Life Easier or Complicated? Increased Risk of Tethering.

BACKGROUND: The present study aims to investigate the frequency of recurrence and tethering effect after only metaphyseal screw removal (sleeper plate technique) compared with the conventional complete plate removal in the treatment of lower extremity deformities with guided growth surgery. METHODS: Seventy-two patients (107 limbs) treated by an 8-plate hemiepiphysiodesis technique around the knee joint were evaluated. After the desired correction, only metaphyseal screw was removed (sleeper plate group) in 35 limbs (25 patients), whereas both screws and plate were removed (plate removal group) in 72 limbs (47 patients). An increase of 5 degrees or more in joint orientation angles in the direction of the initial deformity was considered as recurrence. The rate of rebound, tethering, and maintenance of correction in groups was analyzed at the latest follow-up (mean of 49 mo). RESULTS: The mean age of the patients was 97 months (range: 80 to 129 mo) at the time of index surgery. After a mean of 49 months (range: 16 to 86), 17 (48.5%) limbs maintained the desired stable correction in the sleeper plate group compared with 59 stable limbs (72.2%) in the plate removal group ( P <0.001). There was no statistically significant difference regarding recurrence between the sleeper plate group and the plate removal group (34.3% vs. 27.8%, respectively) ( P =0.216). Reinsertion of the metaphyseal screw was possible 8/12 limbs, and the remaining 4 limbs underwent further surgeries. There were 6 limbs (17.3%) of tethering in the sleeper plate group, and 4/6 limbs required further corrective surgeries. The remaining 2 limbs with slight tethering did not require further surgeries. CONCLUSIONS: Removing only metaphyseal screw increases the risk of tethering. In addition, reinsertion of the screw may not be possible in all cases due to bony growth, and further corrective surgeries may be necessary. Close follow-up is required if the sleeper plate technique is to be applied. LEVEL OF EVIDENCE: Level III.

The Fate of Overcorrection After Hemiepiphysiodesis in Valgus Deformities Around the Knee.

BACKGROUND: Tension band plating is widely used in the surgical treatment of coronal plane deformities around the knee. The rebound phenomenon after implant removal is a common complication of this technique. Overcorrection of joint orientation angles is a method to minimize the effect of the rebound phenomenon. This study aims to investigate the natural course of overcorrected joint orientation angles after plate removal in patients with genu valgum deformity. METHODS: Patients who underwent hemiepiphysiodesis with tension band plating due to genu valgum deformity between 2010 and 2019 were retrospectively analyzed. Mechanical lateral distal femoral angles (mLDFA) and mechanical medial proximal tibial angles were calculated before plate application, before implant removal, and at the last follow-up. At the implant removal, mLDFA>90 degrees and mechanical medial proximal tibial angles <85 degrees were accepted as overcorrected. RESULTS: Seventy-two segments from 45 patients were included. For femoral valgus deformities (n=59), the mean mLDFAs at index surgery, implant removal, and the last follow-up were 79.8±3.9 degrees, 95.5±3.7 degrees, and 87.3±5.1 degrees, respectively. In the more and less than 10 degrees rebound groups, the median age of patients at index surgery were 66 and 101 months ( P =0.04), the mLDFA during implant removal were 97.8 degrees and 94.4 degrees ( P =0.005), and the mean amount of correction in mLDFA was 17 degrees and 13 degrees ( P =0.001), respectively. At the last follow-up, joint orientation angles were found to be still overcorrected in 16 (22%), within normal limits in 36 (50%), and undercorrected in 20 (28%) segments. Ten (13%) segments required additional surgery due to residual deformity. CONCLUSIONS: Overcorrection with tension band plating is an effective modality in the treatment of genu valgum deformity. Rebound after plate removal increases as the age at index surgery decreases and the amount of conscious overcorrection increases. Most segments return to normal joint orientation angle limits after overcorrection. We recommend a mean of 5 degrees routine overcorrection in patients with genu valgum deformity to overcome the rebound phenomenon and to make future interventions easier if ever needed. LEVEL OF EVIDENCE: Level III.