John C. Liu

Transforaminal lumbar interbody fusion: surgical technique and results in 24 patients.

OBJECTIVEThe advantage of anterior column support and fusion in addition to pedicle fixation in patients with degenerative spinal disorders has become increasingly clear. With the increase in popularity of this treatment, a variety of techniques have been used to achieve the goal of anterior column support, fusion, and segmental instrumentation. Posterior lumbar interbody fusion has been used since the late 1940s in the treatment of degenerative lumbar spine. We evaluated a modification to posterior lumbar interbody fusion called transforaminal lumbar interbody fusion (TLIF). METHODSA retrospective analysis was performed on 24 patients (9 women, 15 men) who underwent TLIF. The approach involved a unilateral laminectomy and inferior facetectomy at the level of fusion. The interbody fusion was achieved from this unilateral approach by performing discectomy, arthrodesis, and insertion of one or two titanium cages packed with autologous bone. The average age of the patients in this study was 42.6 ± 12.5 years. Five patients were smokers. Five cases were related to workmen’s compensation. Seventeen patients’ original symptoms were a combination of low back pain and radiculopathy. Ten patients had had a previous spine operation. RESULTSEleven patients had L4–S1 TLIFs. The rest of the patients had a single-level TLIF (L2–S1). Average intensive care unit and floor days were 1.1 ± 1.0 and 5.8 ± 2.2 days, respectively. The number of days to ambulation was 2.8 ± 1.6 days. There were a total of six self-limited complications in 24 patients (including one transient neurological complication). The average follow-up time was 16.9 ± 9.1 months. Twenty-two patients had solid fusions. A modified Prolo scale (4 worst, 20 best) was used to evaluate the clinical outcome. The average score was 16.1 ± 4.1. CONCLUSIONTLIF is a reliable and safe technique for interbody support that can be performed with excellent clinical outcome. In the authors’ experience, TLIF offers excellent exposure with minimal risk. This applies particularly in cases of repeat spine surgery, in which the presence of scar tissue makes traditional posterior lumbar interbody fusion techniques difficult or impossible. In addition, TLIF seems to be a viable alternative to anteroposterior circumferential fusion and/or anterior lumbar interbody fusion.

Changes in coronal and sagittal plane alignment following minimally invasive direct lateral interbody fusion for the treatment of degenerative lumbar disease in adults: A radiographic study - Clinical article

OBJECTIVE The lateral transpsoas approach for lumbar interbody fusion is a minimal access technique that has been used by some to treat lumbar degenerative conditions, including degenerative scoliosis. Few studies, however, have analyzed its effect on coronal and sagittal plane correction, and no study has compared changes in segmental, regional, and global coronal and sagittal alignment after this technique. The object of this study was to determine changes in sagittal and coronal plane alignment occurring after direct lateral interbody fusion (DLIF). METHODS The authors performed a review of the radiographic records of 36 patients with lumbar degenerative disease treated with the DLIF technique. Thirty-five patients underwent supplemental posterior fixation to maintain correction. Preoperative and postoperative standing anteroposterior and lateral lumbar radiographs were obtained in all patients for measurement of segmental and regional coronal and sagittal Cobb angles. Standing anteroposterior and lateral 36-in radiographs were also obtained in 23 patients for measurement of global coronal (center sacral vertebral line) and sagittal (C-7 plumb line) balance. RESULTS The mean coronal segmental Cobb angle was 4.5° preoperatively, and it was 1.5° postoperatively (p < 0.0001). The mean pre- and postoperative regional lumbar coronal Cobb angles were 7.6° and 3.6°, respectively (p = 0.0001). In 8 patients with degenerative scoliosis, the mean pre- and postoperative regional lumbar coronal Cobb angles were 21.4° and 9.7°, respectively (p = 0.0004). The mean global coronal alignment was 19.1 mm preoperatively, and it was 12.5 mm postoperatively (p < 0.05). In the sagittal plane, the mean segmental Cobb angle measured -5.3° preoperatively and -8.2° postoperatively (p < 0.0001). The mean pre- and postoperative regional lumbar lordoses were 42.1° and 46.2°, respectively (p > 0.05). The mean global sagittal alignment was 41.5 mm preoperatively and 42.4 mm postoperatively (p = 0.7). The average clinical follow-up was 21 months in 21 patients. The mean pre- and postoperative visual analog scale scores were 7.7 and 2.9, respectively (p < 0.0001). The mean pre- and postoperative Oswestry Disability Indices were 43 and 21, respectively (p < 0.0001). CONCLUSIONS Direct lateral interbody fusion significantly improves segmental, regional, and global coronal plane alignment in patients with degenerative lumbar disease. Although DLIF increases the segmental sagittal Cobb angle at the level of instrumentation, it does not improve regional lumbar lordosis or global sagittal alignment.

Minimally invasive lateral lumbar interbody fusion and transpsoas approach-related morbidity

OBJECT Recently, the minimally invasive, lateral retroperitoneal, transpsoas approach to the thoracolumbar spinal column has been described by various authors. This is known as the minimally invasive lateral lumbar interbody fusion. The purpose of this study is to elucidate the approach-related morbidity associated with the minimally invasive transpsoas approach to the lumbar spine. To date, there have been only a couple of reports regarding the morbidity of the transpsoas muscle approach. METHODS A nonrandomized, prospective study utilizing a self-reported patient questionnaire was conducted between January 2006 and June 2008 at Northwestern University. Data were collected in 53 patients with a follow-up period ranging from 6 months to 3.5 years. Only 2 patients were lost to follow-up. RESULTS Thirty-six percent (19 of 53) of patients reported subjective hip flexor weakness, 25% (13 of 53) anterior thigh numbness, and 23% (12 of 53) anterior thigh pain. However, 84% of the 19 patients reported complete resolution of their subjective hip flexor weakness by 6 months, and most experienced improved strength by 8 weeks. Of those reporting anterior thigh numbness and pain, 69% and 75% improved to their baseline function by the 6-month follow-up evaluations, respectively. All patients with self-reported subjective hip flexor weakness underwent examinations during subsequent clinic visits after surgery; however, these examinations did not confirm a motor deficit less than Grade 5. Subset analysis showed that the L3-4 and L4-5 levels were most often affected. CONCLUSIONS The minimally invasive, transpsoas muscle approach to the lumbar spine has a number of advantages. The data show that a percentage of the patients undergoing the transpsoas approach will have temporary sensory and motor symptoms related to this approach. The majority of the symptoms are thought to be related to psoas muscle inflammation and/or stretch injury to the genitofemoral nerve due to the surgical corridor traversed during the operation. No major injuries to the lumbar plexus were encountered. It is important to educate patients prior to surgery of the possibility of these largely transient symptoms.

Surgical treatment of fixed cervical kyphosis with myelopathy.

Study Design. A retrospective clinical study. Objective. To investigate clinical and radiographic outcomes following the surgical treatment of fixed cervical kyphosis with myelopathy. Summary of Background Data. To our knowledge, a study specifically addressing the surgical treatment of fixed cervical sagittal deformity has never before been published. Methods. Sixteen patients treated surgically for fixed cervical kyphosis and myelopathy were followed for a mean of 4.5 years (range, 25–112 months). The study group consisted of 9 males and 7 females, with an average age of 52 years (range, 31–78 years). The principal etiologies of cervical deformity were prior laminectomy (63%), advanced spondylosis (19%), infection (6%), neuromuscular disease (6%), and metabolic disease (renal osteodystrophy) (6%). All patients were clinically evaluated by the Nurick classification and Odom criteria both before surgery and at the time of most recent follow-up. Radiographic analysis was performed using thin-cut CT scans, dynamic radiographs, and 14 × 36-inch scoliosis films. Results. The mean preoperative cervical Cobb angle as measured from the C2–C7 was +38° and improved to −10° at final follow-up, yielding an average correction of 48°. The mean number of anterior and posterior segments fused was 4.8 (range, 2–6) and 7.2 (range, 3–14), respectively. The mean Nurick score improved from 2.4 before surgery to 1.5 at the time of follow-up. According to Odom criteria, outcomes were as follows: excellent (38%), good (50%), fair (6%), and poor (6%). At the time of most recent follow-up, solid bony arthrodesis and maintenance of correction occurred in all patients; however, revision was required in one patient. Conclusion. The treatment of fixed cervical kyphosis with myelopathy using circumferential spinal osteotomies and instrumented reconstruction is technically demanding; however, restoration and maintenance of a neutral or lordotic cervical profile and excellent clinical outcomes are achievable.

Muscle flap salvage of spine wounds with soft tissue defects or infection

Study Design. This retrospective study was designed to analyze the results of 22 patients treated for postoperative soft tissue defects of the spine. Objective. To demonstrate the utility of flaps in the salvage of spine wounds. Summary of Background Data. In the literature, the treatment of postoperative spine infections is with serial débridement, antibiotic irrigation catheters, drains, and occasional removal of spinal implants. Muscle flaps have received scant mention in the surgical literature for spine coverage. Methods. Group 1 (n = 15) had postoperative wound infections or dehiscences. Group 2 (n = 7) had “prophylactic” flaps at the time of their initial spine surgery. The indications for “prophylactic” closure included multiple prior surgeries, prior infection, and previous radiation therapy. Group 1 was treated with drainage, dressing changes, and one-stage flap closure of their wounds. Sliding paraspinal muscle flaps were the flaps of choice. Group 2 was treated with a variety of closure techniques at the time of their initial surgery. Results. The average defect size was 10 vertebral bodies long. Despite the large defect size, 19 of 20 surviving patients currently have healed wounds, and all the patients have maintained their instrumentation. Two patients died of causes unrelated to their wound problems. A Group 1 patient with complete loss of a superior gluteal artery flap was salvaged with a contralateral gluteus muscle flap. Another Group 1 patient has intermittent drainage from under a trapezius flap, which covers a cervical spine fusion. Four patients had minor wound complications. Conclusions. Flaps are a useful adjunct in the treatment of patients with complex spine wounds. Sliding paraspinal muscle flaps can effectively close wounds from the high cervical to the low lumbar area in one operative procedure. These patients can go on to successful spine fusion.

Retroperitoneal oblique corridor to the L2–S1 intervertebral discs in the lateral position: an anatomic study

OBJECT Access to the intervertebral discs from L2-S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4-5 disc access, and the L5-S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2-S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus. METHODS Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2-S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2-5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5-S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline. RESULTS The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2-3, 18.60 mm and 25.50 mm; at L3-4, 19.25 mm and 27.05 mm; and at L4-5, 15.00 mm and 24.45 mm. The L5-S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel. CONCLUSIONS The oblique corridor allows access to the L2-S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5-S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2-S1 discs.

Maximizing the potential of minimally invasive spine surgery in complex spinal disorders.

Minimally invasive surgery (MIS) in the spine was primarily developed to reduce approach-related morbidity and to improve clinical outcomes compared with those following conventional open spine surgery. Over the past several years, minimally invasive spinal procedures have gained recognition and their utilization has increased. In particular, MIS is now routinely used in the treatment of degenerative spine disorders and has been shown to be as effective as conventional open spine surgeries. Although the procedures are not yet widely recognized in the context of complex spine surgery, the true potential in minimizing approach-related morbidity is far greater in the treatment of complex spinal diseases such as spinal trauma, spinal deformities, and spinal oncology. Conventional open spine surgeries for complex spinal disorders are often associated with significant soft tissue disruption, blood loss, prolonged recovery time, and postsurgical pain. In this article the authors review numerous cases of complex spine disorders managed with MIS techniques and discuss the current and future implications of these approaches for complex spinal pathologies.

Efficacy of Surgical Preparation Solutions in Lumbar Spine Surgery

BACKGROUND Postoperative spinal wound infections are relatively common and are often associated with increased morbidity and poor long-term patient outcomes. The purposes of this study were to identify the common bacterial flora on the skin overlying the lumbar spine and evaluate the efficacy of readily available skin-preparation solutions in the elimination of bacterial pathogens from the surgical site following skin preparation. METHODS A prospective randomized study was undertaken to evaluate 100 consecutive patients undergoing elective lumbar spine surgery. At the time of surgery, the patients were randomized to be treated with one of two widely used, and Food and Drug Administration (FDA)-approved, surgical skin-preparation solutions: ChloraPrep (2% chlorhexidine gluconate and 70% isopropyl alcohol) or DuraPrep (0.7% available iodine and 74% isopropyl alcohol). Specimens for aerobic and anaerobic cultures were obtained prior to skin preparation (pre-preparation), after skin preparation (post-preparation), and after wound closure (post-closure). A validated neutralization solution was used for each culture to ensure that the antimicrobial activity was stopped immediately after the sample was taken. Positive cultures and specific bacterial pathogens were recorded. RESULTS Coagulase-negative Staphylococcus, Propionibacterium acnes, and Corynebacterium were the most commonly isolated organisms prior to skin preparation. The overall rate of positive cultures prior to skin preparation was 82%. The overall rate of positive cultures after skin preparation was 0% (zero of fifty) in the ChloraPrep group and 6% (three of fifty) in the DuraPrep group (p = 0.24, 95% confidence interval [CI] = 0.006 to 0.085). There was an increase in positive cultures after wound closure, but there was no difference between the ChloraPrep group (34%, seventeen of fifty) and the DuraPrep group (32%, sixteen of fifty) (p = 0.22, 95% CI = 0.284 to 0.483). Body mass index (BMI), duration of surgery, and estimated blood loss did not a show significant association with post-closure positive culture results. CONCLUSIONS ChloraPrep and DuraPrep are equally effective skin-preparation solutions for eradication of common bacterial pathogens on the skin overlying the lumbar spine.

Approach-related complications after decompression for cervical ossification of the posterior longitudinal ligament.

The surgical management of compressive cervical ossification of the posterior longitudinal ligament (OPLL) can be challenging. Traditionally, approach indications for decompression of cervical spondylotic myelopathy have been used. However, the postoperative complication profile after cervical OPLL decompression is unique and may require an alternative approach paradigm. The authors review the literature on approach-related OPLL complications and suggest a management strategy for patients with single- or multiple-segment OPLL with or without greater than 50% canal stenosis.

Is laparoscopic anterior lumbar interbody fusion a useful minimally invasive procedure

OBJECTIVE Laparoscopic anterior lumbar interbody fusion (LALIF) has been demonstrated to be safe and effective. Its use as a standard surgical technique has been recommended for arthrodesis in the lumbosacral region. We reviewed our experience with LALIF for safety, effectiveness, and usefulness. METHODS Retrospective review of 14 patients who underwent LALIF was performed. All patients had a diagnosis of degenerative disc disease with medically retractable mechanical back pain. RESULTS No intraoperative vascular or neurological injury was encountered. An average operating time of 300 minutes with blood loss of 60 ml was found. The average hospital stay was 3.4 days. At 3 to 6 months after surgery, 80% fusion rates were achieved. CONCLUSION Although LALIF is a safe and effective procedure, it has many disadvantages, which make it a less than optimal procedure for routine use. Other minimally invasive approaches to the anterior lumbar spine result in similar beneficial results without the drawbacks associated with LALIF.