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  • Author or Editor: Amer F. Samdani x
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Daniel M. Sciubba, R. Morgan Stuart, Matthew J. McGirt, Graeme F. Woodworth, Amer Samdani, Benjamin Carson and George I. Jallo

Object

The majority of shunt infections occur within 6 months of shunt placement and chiefly result from perioperative colonization of shunt components by skin flora. Antibiotic-impregnated shunt (AIS) systems have been designed to prevent such colonization. In this study, the authors evaluate the incidence of shunt infection after introduction of an AIS system in a population of children with hydrocephalus.

Methods

The authors retrospectively reviewed all pediatric patients who had undergone cerebrospinal fluid (CSF) shunt insertion at their institution over a 3-year period between April 2001 and March 2004. During the 18 months prior to October 2002, all CSF shunts included standard, nonimpregnated catheters. During the 18 months after October 2002, all CSF shunts included antibiotic-impregnated catheters. All patients were followed up for 6 months after shunt surgery, and all shunt-related complications, including shunt infection, were evaluated. The independent association of AIS catheter use with subsequent shunt infection was assessed via multivariate proportional hazards regression analysis.

A total of 211 pediatric patients underwent 353 shunt placement procedures. In the 18 months prior to October 2002, 208 (59%) shunts were placed with nonimpregnated catheters; 145 (41%) shunts were placed with AIS catheters in the 18 months after October 2002. Of patients with nonimpregnated catheters, 25 (12%) experienced shunt infection, whereas only two patients (1.4%) with antibiotic-impregnated catheters experienced shunt infection within the 6-month follow-up period (p < 0.01). Adjusting for intercohort differences via multivariate analysis, AIS catheters were independently associated with a 2.4-fold decreased likelihood of shunt infection.

Conclusions

The AIS catheter significantly reduced incidence of CSF shunt infection in children with hydrocephalus during the early postoperative period (< 6 months). The AIS system used is an effective instrument to prevent perioperative colonization of CSF shunt components.

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Shabbar F. Danish, Amer Samdani, Amgad Hanna, Phillip Storm and Leslie Sutton

Object

Posterior fossa decompression with duraplasty is routinely used for the treatment of Chiari malformations. It has been traditionally believed that this procedure requires a watertight seal with primary closure of the dura with either pericranium or allograft. In this study, the authors evaluated two synthetic dural substitutes in this patient population for feasibility of use and identification of perioperative morbidity.

Methods

The authors evaluated 56 patients who underwent duraplasty with a synthetic collagen matrix (Dura-Gen) after suboccipital craniectomy and C-1 laminectomy, and 45 patients in whom the dural closure involved acellular human dermis (AlloDerm). Patients in both groups were assessed for the presence of a pseudomeningocele, wound infection, cerebrospinal fluid (CSF) leak, and the need for repeated operation either for wound revision or the placement of a ventriculoperitoneal shunt. Operative times for which DuraGen duraplasty was used were compared with those for AlloDerm closure.

In the DuraGen group, complications included five pseudomeningoceles (8.9%), two wound infections (3.6%), one CSF leak (1.8%), and four repeated operations (three shunt revisions and one reexploration; 7.1%) in nine patients. In the AlloDerm group, there were five pseudomeningoceles (11.1%), one wound infection (2.2%), one CSF leak (2.2%), and two repeated operations (two shunt revisions; 4.4%) in seven patients. The operative time associated with DuraGen was significantly shorter than that of duraplasty that required closure with sutures (92 minutes compared with 128 minutes, p < 0.01).

Conclusions

The synthetic dural substitutes DuraGen and AlloDerm provide a suitable alternative duraplasty with comparable complication rates. DuraGen requires a significantly shorter operative time than AlloDerm.

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Graeme F. Woodworth, Matthew J. McGirt, Amer Samdani, Ira Garonzik, Alessandro Olivi and Jon D. Weingart

Object

The gold standard for stereotactic brain biopsy target localization has been frame-based stereotaxy. Recently, frameless stereotactic techniques have become increasingly utilized. Few authors have evaluated this procedure, analyzed preoperative predictors of diagnostic yield, or explored the differences in diagnostic yield and morbidity rate between the frameless and frame-based techniques.

Methods

A consecutive series of 110 frameless and 160 frame-based image-guided stereotactic biopsy procedures was reviewed. Associated variables for both techniques were reviewed and compared. All stereotactic biopsy procedures were included in a risk factor analysis of nondiagnostic biopsy sampling.

Frameless stereotaxy led to a diagnostic yield of 89%, with a total permanent morbidity rate of 6% and a mortality rate of 1%. Larger lesions were fivefold more likely to yield diagnostic tissues. Deep-seated lesions were 2.7-fold less likely to yield diagnostic tissues compared with cortical lesions. Frameless compared with frame-based stereotactic biopsy procedures showed no significant differences in diagnostic yield or transient or permanent morbidity. For cortical lesions, more than one needle trajectory was required more frequently to obtain diagnostic tissues with frame-based as opposed to frameless stereotaxy, although this factor was not associated with morbidity.

Conclusions

With regard to diagnostic yield and complication rate, the frameless stereotactic biopsy procedure was found to be comparable to or better than the frame-based method. Smaller and deep-seated lesions together were risk factors for a nondiagnostic tissue yield. Frameless stereotaxy may represent a more efficient means of obtaining biopsy specimens of cortical lesions but is otherwise similar to the frame-based technique.

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Joseph C. Noggle, Daniel M. Sciubba, Amer F. Samdani, D. Greg Anderson, Randal R. Betz and Jahangir Asghar

Object

Lumbar spondylolysis occurs in approximately 6% of the population and presents with localized mechanical back pain, often in young athletes. Surgical treatment may involve decompression, lumbar intersegmental fusion, or direct repair of pars defects. Although such open procedures may effectively resolve symptoms, minimal-access approaches may additionally decrease collateral damage to soft tissues, allowing young, active patients to resume athletic activities sooner. In this study, the authors review their experience repairing bilateral lumbar spondylolyses with screw and hook constructs placed via a minimal-access approach.

Methods

Five consecutive pediatric patients with bilateral L-5 spondylolysis were treated. Bilateral incisions (2.5 cm) were made over L-5. Exposure was maintained with bilateral expandable tubular retractor systems. Pedicle screws were placed in the L-5 pedicles and attached to hooks under the L-5 laminae. A direct repair was performed at the pars defect. Clinical characteristics, operative variables, and postoperative outcomes were collected.

Results

All 5 patients underwent surgery; 4 were male (80%) and 1 was female (20%), and the mean age was 15.8 years (range 15–17 years). The mean estimated blood loss and duration of surgery were 37 ml (range 15–75 ml) and 1.94 hours (range 1–3 hours), respectively. Postoperative hospital stays ranged from 1 to 3 days (mean 1.8 days). The only complication occurred in 1 patient who experienced minor superficial wound breakdown. All patients have experienced resolution of symptoms at this preliminary stage, which has continued over an 8-month follow-up period.

Conclusions

Lumbar spondylolysis can be adequately and safely treated via minimal-access surgical repair of the pars interarticularis by using pedicle screws and rod-hook constructs. This approach may decrease the collateral soft tissue damage common to open dissections, and may be ideal for young, active surgical candidates.

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Amer F. Samdani, Ashish Ranade, Henry J. Dolch, Reed Williams, Tricia St. Hilaire, Patrick Cahill and Randal R. Betz

Object

Few options exist for the treatment of severe, early onset scoliosis. Goals of treatment include stabilizing curve progression while allowing for normal spine, chest, and lung growth. The vertical expandable prosthetic titanium rib (VEPTR) is a novel device designed to control the spine deformity while permitting lung and spine growth. In this paper the authors report their experience with using bilateral VEPTRs from the ribs to the pelvis for children with severe, early onset scoliosis.

Methods

Eleven children were identified who had been treated with bilateral VEPTRs from the ribs to the pelvis. The authors conducted a retrospective review and collected the following data: clinical diagnosis, age at surgery, number of lengthening procedures, and complications. In addition, pre- and postoperative radiographs were reviewed to measure maximum Cobb angle (both thoracic and lumbar), thoracic height, total spine height as measured from T-1 to S-1, thoracic kyphosis (T2–12), and lumbar lordosis (L1–S1).

Results

The average patient age at surgery was 71 months; the mean preoperative thoracic Cobb angle was 81.7°. This angle was corrected to 50.6° immediately postoperatively, and this correction was maintained; at the most recent follow-up the curves averaged 58°. Similarly, the preoperative kyphosis (T2–12) angle measured 43° preoperatively, 23° immediately postoperatively, and 37° at the most recent follow-up evaluation. The patients underwent a total of 41 lengthening procedures (average 3.7 lengthening procedures per patient), and overall spine length increased from 23.1 cm preoperatively, to 27.3 cm immediately postoperatively, to 29.4 cm at the final follow-up (an average of 25 months). Four (36.4%) of the 11 patients experienced complications.

Conclusions

The VEPTR offers a viable treatment option for children with severe, early onset scoliosis. It achieves and maintains spinal deformity correction, while allowing for continued spine and chest-wall growth. Complication rates are similar to those reported for other growing systems.

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Editorial

Infantile idiopathic scoliosis

Mark F. Abel

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Jason R. Smith, Amer F. Samdani, Joshua Pahys, Ashish Ranade, Jahangir Asghar, Patrick Cahill and Randal R. Betz

Object

There are few data on treatment results for patients with idiopathic infantile scoliosis (IIS). Thus, the authors have performed a retrospective review of their experience with treating these patients, particularly as newer technologies, such as the vertical expandable prosthetic titanium rib (VEPTR), emerge.

Methods

This retrospective study was conducted to evaluate the methods of treatment used to manage IIS at a single institution. The authors reviewed 31 consecutive patients with a primary diagnosis of IIS. Patients were screened to ensure that there were no confounding congenital anomalies or comorbidities that may have contributed to the spinal deformity. The average age at the time of initial treatment was 25 months. Treatment modalities included bracing, serial body casting, and VEPTR. Pretreatment, posttreatment, and most recent Cobb angles were compared to assess the overall curve correction, and patient charts were reviewed for the occurrence of complications.

Results

Of the 31 patients, 17 were treated with a brace, 9 of whom had curve progression and went on to other forms of treatment. Of the 8 who did respond, there was an overall improvement of 51.2%. The 10 patients who received body casts, who had a mean preoperative Cobb angle of 50.4°, demonstrated an average correction of 59.0%, with only a few skin irritations reported. The 10 patients treated with VEPTR devices demonstrated a mean preoperative Cobb angle of 90.0°, and an average correction of 33.8% was attained. Three of the VEPTR-treated patients (33%) experienced minor problems.

Conclusions

The authors' results suggest that body casting has utility for appropriately selected patients; that is, those with smaller, flexible spinal curves. Bracing had limited utility, with high levels of progression and the need for secondary treatments. The VEPTR device appears to be a viable alternative for large-magnitude curves.

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Amer F. Samdani, Anthony L. Fine, Sukhdeep S. Sagoo, Shailja C. Shah, Patrick J. Cahill, David H. Clements and Randal R. Betz

Object

Tethering of the spinal cord is thought to increase the chance of neurological injury when scoliosis correction is undertaken. All patients with myelomeningocele (MM) are radiographically tethered, and untethering procedures carry significant morbidity risks including worsening neurological function and wound complications. No guidelines exist as regards untethering in patients with MM prior to scoliosis correction surgery. The authors' aim in this study was to evaluate their experience in patients with MM who were not untethered before scoliosis correction.

Methods

Seventeen patients with MM were retrospectively identified and 1) had no evidence of a clinically symptomatic tethered cord, 2) had undergone spinal fusion for scoliosis correction, and 3) had not been untethered for at least 1 year prior to surgery. The minimum follow-up after fusion was 2 years. Charts and radiographs were reviewed for neurological or shunt complications in the perioperative period.

Results

The average age of the patients was 12.4 years, and the following neurological levels were affected: T-12 and above, 7 patients; L-1/L-2, 6 patients; L-3, 2 patients; and L-4, 2 patients. All were radiographically tethered as confirmed on MR imaging. Fourteen of the patients (82%) had a ventriculoperitoneal shunt. The mean Cobb angle was corrected from 82° to 35°, for a 57% correction. All patients underwent neuromonitoring of their upper extremities, and some underwent lower extremity monitoring as well. Postoperatively, no patient experienced a new cranial nerve palsy, shunt malfunction, change in urological function, or upper extremity weakness/sensory loss. One patient had transient lower extremity weakness, which returned to baseline within 1 month of surgery.

Conclusions

The study results suggested that spinal cord untethering may be unnecessary in patients with MM who are undergoing scoliosis corrective surgery and do not present with clinical symptoms of a tethered cord, even though tethering is radiographically demonstrated.

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Steven W. Hwang, Amer F. Samdani, Mark Tantorski, Patrick Cahill, Jason Nydick, Anthony Fine, Randal R. Betz and M. Darryl Antonacci

Object

Several studies have characterized the relationship among postoperative thoracic, lumbar, and pelvic alignment in the sagittal plane. However, little is known of the relationship between postoperative thoracic kyphosis and sagittal cervical alignment in patients with adolescent idiopathic scoliosis (AIS) treated with all pedicle screw constructs. The authors examined this relationship and associated factors.

Methods

A prospective database of pediatric patients with AIS undergoing spinal fusion between 2003 and 2005 was reviewed for those who received predominantly pedicle screw constructs for Lenke Type 1 or Type 2 curves. Parameters analyzed on pre- and postoperative radiographs were the fusion levels; cervical, thoracic, and lumbar sagittal balance; and C-2 and C-7 plumb lines.

Results

Preoperatively, 6 (Group A) of the 22 patients included in the study had frank cervical kyphosis (mean angle 13.0°) with mean associated thoracic kyphosis of 27.2° (range 16°–37°). Postoperatively, cervical kyphosis (13.0°) remained in the patients in Group A along with mean thoracic kyphosis of 17.7° (range 4°–26°, p < 0.05). Preoperatively, the remaining 16 of 22 patients had neutral to lordotic cervical alignment (mean −13.8°) with thoracic kyphosis (mean 45°, range 30°–76°). Postoperatively, 8 (Group B) of these 16 patients demonstrated cervical sagittal decompensation (> 5° kyphosis), with 6 showing frank cervical kyphosis (10.5°, p < 0.05). In Group B, the mean postoperative thoracic kyphosis was 25.6° (range 7°–49°, p < 0.05). The other 8 patients (Group C) had mean postoperative thoracic kyphosis of 44.1° (range 32°–65°), and there was no cervical decompensation (p < 0.05).

Conclusions

The sagittal profile of the thoracic spine is related to that of the cervical spine. The surgical treatment of Lenke Type 1 and 2 curves by using all pedicle screw constructs has a significant hypokyphotic effect on thoracic sagittal plane alignment (19 [86%] of 22 patients). If postoperative thoracic kyphosis is excessively decreased (mean 25.6°, p < 0.05), the cervical spine may decompensate into significant kyphosis.